Thanks for following this live commentary from Stamford Bridge. I've been Matt Addison. On the day Chelsea went top of the Premier League - until tomorrow at least - and Unai Emery realised the scale of the task he has on his hands, it has been a pleasure. What a remarkable match!
Chelsea seem to have adapted much better to the style of their new boss, and have Hazard in their armoury. New signing Kovacic also looked good when he came on; alongside Kante and Jorginho, who were both excellent, he could complete a very good midfield trio, with Barkley also in the mix.
In attack, Arsenal must be far more clinical in future, but it is in defence that they have real concerns. Of course, they have played both Manchester City and Chelsea in their first two matches, but even so, familiar failures are holding them back.
It was a great game for the neutral, with five goals shared and very little in the way of defending. Chelsea go top after two games, while Arsenal are 17th.
Chelsea were worthy winners on the balance of play. Arsenal were disappointing until they mounted an unlikely comeback from two goals down, but then dropped deep in the second period and invited Chelsea on to them. In the end, it took Hazard coming off the bench to engineer a chance for Alonso to win the game.
FULL-TIME! Sarri's first home game as Chelsea boss ends in a 3-2 victory.
90+3' Giroud and Hazard break clear and should score, but Cech saves.
90+2' Kante breezes past Bellerin on the left. He has been very good again today.
90+1' Kepa is pressured into playing his clearance out of play. Arsenal have the ball, but are in need of a goal.
90' Ramsey volleys over from 25 yards. It was a good effort and went only narrowly over Kepa's crossbar. There will be three added minutes.
89' Bellerin overhits his cross into the penalty area and it goes out for a goal kick. Arsenal need better than that at this stage.
87' Alonso has all the time in the world to find a Chelsea shirt in the box, and he gives it to Giroud, who forces another stop from Cech.
86' Hazard finds a way past about five players before drawing a good save from Cech. He is so good at dropping his shoulder and beating players.
85' Lacazette wins the ball from Hazard, but referee Atkinson awards the Belgian a free-kick.
84' Monreal is almost caught in possession by Kante but buys a free-kick to get himself out of trouble. Arsenal certainly cannot afford to concede again at this stage.
83' The corner comes to nothing, but in this game, Arsenal have already come back once, so do not rule them out doing it again.
82' Arsenal have a free-kick on their left-hand side where they can fight back. Mkhitaryan takes and it goes out for a corner.
GOAL! Yes, we will find a winner! Alonso sweeps home a pass from Hazard, who beat his man with ease on the left side. Lacazette lost possession poorly and then failed to track back, and Chelsea lead.
80' It's been a much more defensive game in the second half. With ten minutes to go, will we find a winner?
79' Chance for Kante, who finds himself unmarked having made a late run into the box. His header goes well over the bar.
77' Ramsey crosses and Kepa just about grabs the ball at the second attempt, with Lacazette in the vicinity. Mustafi is then booked for a foul on Hazard.
76' Big chance for Monreal, but he slips as he shoots and Azpilicueta can block. Lacazette's first touch of the game set him up.
Subs: Iwobi is replaced by Lacazette and Giroud comes on for Morata.
74' Azpilicueta fouls Guendouzi.
73' Luiz shoots from the set-piece, and Cech beats away from danger well with no fuss.
72' Kovacic is scythed down by Torreira on the edge of the box. Big chance for Chelsea here. Hazard was again the creator, with a brilliant drag-back into Kovacic's path.
70' Hazard flashes a cross right across the face of goal, but there is no one there to turn it in.
69' Just over twenty minutes to go, and Chelsea look the more likely at the moment. With Hazard on the pitch, they have an additional threat.
Arsenal sub: Ramsey comes on for Ozil. The German has done very little so far, so the change makes perfect sense.
66' Iwobi is fouled by Rudiger. He was fortunate because he had already lost control of the ball.
65' All Chelsea now as Pedro's shot from the edge of the area is closed down.
64' Hazard twists and turns before letting rip from distance. He won a corner, which led to Cech making a simple save.
63' Morata forces Cech into a good one-v-one save, but is called offside.
62' Both Chelsea subs get early touches of the ball as Chelsea play around Arsenal. The Gunners are beginning to sit very deep.
Chelsea subs: Willian and Barkley are replaced by Hazard and Kovacic.
60' Iwobi tries to slot a pass through but there is no one there and his ball goes through for a goal kick.
58' Aubameyang finds the back of the net, but he was flagged offside well before that. Again, he does not need to go that soon. Ozil's ball into him was perfect.
57' Good save from Cech as Barkley tees himself up and strikes low. The England international has looked confident this evening.
56' Luiz attacked the kick but it was headed clear. Chelsea regain possession as they look to retake the lead.
55' Morata makes a good run in behind and wins a corner off Mustafi.
54' Alonso looks to play in Willian but the Spaniard overhits his pass and the ball runs for an Arsenal goal kick.
53' Aubameyang is caught offside. He did not need to make his run so early, and had he held it, he would have been in.
52' Kante shoots towards goal and there are claims of a handball, but nothing is given. It would have been harsh.
51' Morata is fouled by Mustafi, and the early Arsenal pressure eases slightly.
49' Both Hazard and Kovacic are warming up for Chelsea. You would imagine that both will enter the fray at some stage, perhaps sooner rather than later.
48' Barkley evades two challenges well and tries to play Morata in. The ball rebounds back towards him having been blocked, but he cannot quite get there. Instead, Pedro fires over the top.
47' Arsenal seem to have started the second half in the way manner they ended the first, with Iwobi involved. Aubameyang crosses dangerously, but Ozil cannot connect.
46' The second half has begun.
Half-time change: Torreira replaces Xhaka for Arsenal.
It will be interesting to see whether the game can continue at this intensity, as it has been frenetic so far. N'Golo Kante has been everywhere as usual.
Let's hope that this enthralling encounter continues to excite in the second half. For now, though, both teams need a breather - as do all those who are purely spectators.
HALF-TIME. Martin Atkinson ends the first half, and what a half it has been. From nowhere, Arsenal have got themselves level, but with the chances for both sides, it could be 4-4.
45+1' Another miss from Arsenal, and this time it is Iwobi. He is unmarked from the penalty spot. Chelsea are all over the place!
45' There will be two added minutes.
44' Arsenal, somehow, look the more likely now. Aubameyang shoots just wide from eight yards, and the Gunners do not want half-time to come. What a game we have on our hands.
43' Guendouzi hits one from distance, and Kepa saves. The game has ignited just before the interval.
GOAL! It's 2-2 and Iwobi is the goal scorer! From nothing, Arsenal are back in the game. Mkhitaryan's low cross found the winger, who was unmarked from close range.
40' Pedro is offside when Luiz looked to feed him in over the top of the high Arsenal line.
39' Headed clear by Arsenal, who suddenly have a spring in their step for the first time in the game.
38' Great save from Cech as Morata shoots from distance. Corner to Chelsea.
GOAL! Mkhitaryan gets one back from the edge of the penalty area! That's much better from Arsenal's number seven, who finished well when the ball fell to him. 2-1.
36' Pedro shoots tamely from the edge of the box. He had Alonso up with him but chose to go alone.
34' Ten minutes or so to go until the break. Arsenal have had two huge opportunities and converted neither, and have afforded Chelsea too much space and time for most of the game to this point. Sarri will be very happy with his players.
31' ANOTHER HUGE CHANCE GOES OVER! This time it is Mkhitaryan who blazes over from a similar position as Aubameyang a few minutes ago. It was a difficult shot to execute, but the Armenian should have done a lot, lot better there.
30' Emery is fuming on the touchline. With a third of the game gone, Arsenal have been poor.
29' Monreal lets the ball slip out of play under no pressure at all as Arsenal try and play out from the back. It has been that kind of performance from them so far.
28' Morata is caught by Mustafi, giving Chelsea an opportunity to put the ball into the box. Alonso heads the ball down, but Arsenal do enough to clear their lines.
27' Xhaka goes into the book for a late challenge on Pedro.
26' Morata chases back and wins it off Guendouzi, who was dallying on the ball. Jorginho, in contrast, has been the best player on the pitch in the opening half an hour.
24' Willian almost puts Morata in again, but Mustafi is able to get something on the ball this time.
22' What a few moments those were, and how crucial they could be in deciding the game. Arsenal now have a mountain to climb.
GOAL! Morata makes it 2-0, when Aubameyang should have just equalised at the other end. More poor defending from Arsenal - it was one ball over the top that undid them, 55 seconds after they should have made it 1-1.
19' HUGE CHANCE FOR AUBAMEYANG! From six yards out, the striker shoots over. Bellerin was in behind having been played in well by Guendouzi; he squared it and the forward shot miles over when it seemed harder to miss.
17' Aubameyang gets behind Luiz, but his shot from the angle is simple enough for Kepa to pick up, albeit at the second attempt after an initial fumble.
16' Alonso gets in behind Bellerin far too easily, but overhits his cross and it goes all the way over for a throw-in by the corner flag.
14' Chelsea are all over Arsenal at the moment. If it carries on like this, the game could be over by half-time. Emery's men need to get hold of the ball for a minute, but the waves of Chelsea attacks continue.
13' Kante drives forward from midfield in his new, free role, and sets up Barkley, who shoots just over the top from the edge of the area.
12' Morata chases down Cech, who clears his lines just in time. Arsenal's defence, in particular, do not look comfortable.
11' Chelsea have been much the better side early on and are value for their lead. It is the home side with of the ball now, and they are a goal to the good.
GOAL! Alonso sets up Pedro, who slides past Cech from ten yards, having been left unmarked. Woeful defending from Arsenal. 1-0.
8' Chance for Ozil! Monreal overlaps Iwobi, recieves the ball, and crosses. The German got a lot on the cross but could only divert it a couple of yards wide on the volley.
7' Barkley has been central early on for the hosts. Sarri has trusted him in both of Chelsea's matches early in the season, and he has impressed so far.
6' Jorginho plays a lofted pass towards Barkley, who is onside but cannot collect it. He would have been in acres of space with only Cech to beat. Fortunate from Arsenal's perspective.
5' It's been a quick start to the game here, with Chelsea on the front-foot. Morata is almost squeezed through on goal but Sokratis intercepts.
4' Pedro drives inside from the right-hand side and fires in a shot which sails wide. Emery will want his players to close down a little faster than they did there.
3' Monreal heads clear a long cross-field pass from Luiz which was heading into the path of Pedro. Luiz's long shot then drifts well over the bar from 30 yards.
1' Early chance for Aubameyang who scuffs a shot towards Kepa. There was no pace on the effort and the goalkeeper can bend down and collect it with ease.
KICK-OFF! It is Arsenal who get the game underway.
The players are coming out of the tunnel and we are almost ready for kick-off.
Just over ten minutes until kick-off, now, and Stamford Bridge is filling up. Stay with us for live updates throughout the biggest English match of the weekend.
Emery on new midfielder Torreira, who starts today's game as a substitute: "He is now with the team and learning English conversation with us, and can understand all the things we want to do tactically on the pitch. The first match against City, he played 15-20 minutes and I think this is good - I want to continue with him improving."
Sarri on Morata, who missed several chances last week against Huddersfield: "I am not worried. He is a great player. In this moment, he only needs to gain confidence. He needs to score, as do all the strikers in the world. He is improving."
While we wait for kick-off here at Stamford Bridge, which is just over half an hour away, take a look at Danial Kennedy's match preview. Both sides are now out on the pitch warming up.
Results from elsewhere in the Premier League today:
Cardiff 0-0 Newcastle United
Leicester City 2-0 Wolves
West Ham United 1-2 Bournemouth
Everton 2-1 Southampton
Tottenham 3-1 Fulham
For the visitors, summer signing Torreira starts on the bench again, while Alex Iwobi comes in for Aaron Ramsey. Matteo Guendouzi and Granit Xhaka will be the midfield holders. Nacho Monreal is fit to start at left back.
Chelsea, then, are unchanged from their win over Huddersfield, meaning Eden Hazard begins the game on the bench once again. Ross Barkley gets another opportunity to impress playing in the midfield three.
Arsenal subs: Leno, Lichtsteiner, Elneny, Torreira, Ramsey, Welbeck, Lacazette
Chelsea subs: Caballero, Christensen, Zappacosta, Moses, Hazard, Kovacic, Giroud
Arsenal starting XI: Cech, Bellerin, Sokratis, Mustafi, Monreal, Xhaka, Guendouzi, Mkhitaryan, Ozil, Iwobi, Aubameyang
Chelsea starting XI: Kepa, Azpilicueta, Rudiger, Luiz, Alonso, Jorginho, Kante, Barkley, Willian, Pedro, Morata
Official team news should news is expected to come through at 4:30pm BST, an hour before the match begins. Stay tuned for all the build-up as we count down to kick-off!
These two teams are familiar foes having faced each other several times last season. Arsenal won the Community Shield on penalties last August after the game finished 1-1, before a goalless draw at Stamford Bridge in the league in September. The reverse fixture ended 2-2 at the Emirates. Arsenal prevailed in the EFL Cup semi-final, beating Chelsea 2-1 on aggregate. Arsenal also won on penalties against Chelsea in pre-season following another 1-1 draw in the International Champions Cup.
Arsenal team news: Stephan Lichtsteiner will start the game in place of the injured Ainsley Maitland-Niles; Uruguayan Lucas Torreira is expected to make his first start for the club in midfield; Sokratis Papastathopoulous is also expected to start with Laurent Koscielny and Sead Kolasinac both ruled out.
Chelsea team news: New signing Mateo Kovacic, signed on a season-long loan from Real Madrid in the summer could make his debut; Eden Hazard could make his first start of the season having begun the Huddersfield game on the bench after his World Cup exploits; world-record goalkeeper Kepa Arrizabalaga will retain his place having kept a clean sheet on his debut. Cesc Fabregas is also out through a minor injury.
The referee for this match is Martin Atkinson. He took charge of three of Chelsea's league games last season, and they lost all of them, against Manchester City, Manchester United and Newcastle United. He also oversaw two Arsenal games, with them winning one and drawing one.
It is a game neither side will want to lose, particularly given the circumstances. Emery has lost his only competitive game in charge of Arsenal so far and will want to pick up some points as soon as possible, while this is Sarri's first Stamford Bridge game as Chelsea manager.
This top-six clash is Chelsea's first real test of the season, then, under new boss Maurizio Sarri. For Arsenal and Unai Emery, it is the second successive week that they have faced one of the big teams who will compete in the upper echelons of the Premier League.
The Blues opened their campaign with a comfortable three-goal victory away at Huddersfield Town with N'Golo Kante, Jorginho and Pedro on the scoresheet, while the Gunners were beaten 2-0 at home by champions Manchester City on the opening day.
Hello and welcome to this live text commentary of Chelsea against Arsenal with me, Matt Addison.