They are on 10 points after five games, whilst Köln are now level on points with Red Star, and any winner between the two in Serbia in two weeks’ time will qualify in second place. A draw and a win for BATE against Arsenal at the Emirates would see them through instead. If not, Red Star would go through due to their 1-0 win against Köln in September.
It was another limp display in the Europa League for Arsenal though, but most of the hard work was done in the first three matches and they will finish as group winners and seeds for the last-32 draw next month.
A famous win for the Billy Goats that will surely go down in the club's folklore. Guirassy's penalty - as debatable as the awarding of it was - proves to be the difference as the Bundesliga's bottom side battle, almost literally, to victory. Jannes Horn was clearly still hobbling after the final, whilst Timo Horn and Rausch may have been struggling at the end too.
FULL TIME. KÖLN 1-0 ARSENAL.
90+4: Final minute.
The Köln fans must be right on the edge of the seats right now. Only three wins all season, and one of those was against a lower-league side.
90+2: Close! Nketiah passes back to Wilshere, who fires on goal, but it's tipped over by Horn. The keeper also takes the corner from Elneny.
Four minutes added on in Germany but whatever they do top spot is now confirmed. They will still want something though.
FULL TIME IN BELARUS. 0-0. ARSENAL WIN GROUP H.
90: Arsenal look nervous as they try to play it out from the back. Rob Holding loses it but they quickly regain possession.
89: Oooh. Some brilliant skill from Nelson as he weaves his way through the defence, but Horn saves. A chance then for Nketiah but it's out for a goal-kick.
88: Wilshere dispossessed by, I think, Lehmann. Köln try to build their own attack but it boils out. Guirassy then earns a booking for a foul on Mertesacker.
85: Another ball into the box. Wilshere does find Giroud but he can only get the slightest of touches with his head.
84: Attacking change for Arsenal. Debuchy makes way for Eddie Nketiah - can he repeat his Norwich City heroics? Chants of "Eddie, Eddie" just audible from the Arsenal fans.
Iñaki Williams has plus Bilbao ahead against Hertha, 3-2 there.
83: Olkowski cross blocked. Appeals for handball ignored.
82: A Giroud cross is just over the head of Wilshere. Giroud hasn't really been involved that much, he's probably had more crosses than shots this evening.
80: Jannes Horn has made it back onto the pitch, by the way. A cross from Maitland-Niles is easily taken by the other Horn, Timo.
78: Wilshere takes the corner this time. Much better, although Mertesacker is beaten to the header in the box.
78: The stretcher is out for Jannes Horn - the last thing they need is yet another injury. They've already used all three subs too. He has walked off though.
76: A big chance for Giroud, picking up a long ball, but both Horns deal with him, Jannes with a good challenge as Horn comes in, and the ball goes out. Both Köln players need treatment after that.
75: Another Arsenal move breaks down but they get a corner. Yet another poor one from Elneny. A concern just now as Wilshere was on the floor, but he's got back up without needing any treatment.
73: An Elneny cross can't find Giroud in the box. Final Köln change, Osako makes way for Lehmann as Peter Stöger looks to hold on to these valuable three points.
An update from elsewhere - Aduriz has scored again from the spot to make it 2-2 between Athletic and Hertha. Still 0-0 in Belarus between BATE and Red Star - so as it stands Arsenal would still win the group tonight, but Köln would be right back in contention to qualify as well.
69: Köln attacking with a bit more confidence now, although Rausch puts his cross the wrong side of Osako.
67: A cross from Chambers aimed at Wilshere but he heads out as he goes for the ball with Sörensen. Chambers is then taken off for Nelson, a more attacking option.
66: A little more urgency from the Gunners. Wilshere has a pop, but Horn is equal to it.
64: Arsenal pay the price for not making their dominance count. They have a corner though, and at last Elneny puts in a good delivery. Mertesacker heads it at Horn.
62: Guirassy steps up to take the penalty he earned himself. Ospina goes to his right, Guirassy fires it straight down the middle. That has gone down well in Cologne!
GOAL KÖLN! 1-0.
61: Wow. Guirassy goes down with defenders either side of him. Debuchy appears to push him down, but his fellow Frenchman goes down pretty easily.
60: A decent chance for the hosts! An Arsenal header falls to Milos Jojic, who sets up Guirassy, but it's a weak shot and easily taken by Ospina.
Córdoba was very quiet and Köln have tweeted he has a knock. Not a surprise, he was shown grimacing a couple of times by the cameras during the first half. He's only just come back from a hamstring injury - not that he has done much when he's been fit since moving from Mainz in the summer.
57: The free-kick from that foul leads to a corner, but Elneny takes it short and it inevitably leads to nothing.
56: A couple of attacks for Arsenal, coming through Wilshere, but neither come to anything. Klünter then earns a yellow card for a foul on Maitland-Niles out wide. And there's a sub as well - Córdoba replaced by Pawe? Olkowski for Köln.
53: Córdoba puts a ball into the box for the hosts, trying to find Guirassy, but Ospina collects it in the air.
52: Another corner for the Gunners. Again Elneny can only find Guirassy. None of Arsenal's three corners have posed any threat.
50: An Arsenal corner doesn't make it past the first man as Guirassy heads it clear.
48: Nearly a chance for Arsenal, Wilshere just loses the ball in the box though. As the hosts look to counter, Mathieu Debuchy brings it to a halt and is booked for the foul.
46: We're back underway for the second half. There has been a change - Iwobi makes an early apperance with Welbeck making way, Wenger presumably thinking 45 minutes is enough for him for now.
Köln have been flat, with only a couple of chances worth speaking of. They look bereft of all confidence.
Something and nothing in the first half. Arsenal have been dominant, but knowing they're already through and only need a draw to confirm top spot, there's been no real urgency in their attacking play.
HALF TIME. KÖLN 0-0 ARSENAL.
45+1: An attack for the home side to get their fans excited about - until the end up passing all the way back to Horn that is.
Two added on.
45: Elneny has a go from distance. Horn has absolutely nothing to worry about as it sails over.
43: Another free-kick to Arsenal, taken by Elneny again but punched away by Horn.
42: A promising moment for the hosts. Rausch and Osako bring the ball forward down the left, but the latter's cross leaves a lot to be desired. They've offered very little in an attacking sense so far.
Drama in Spain by the way. Aritz Aduriz equalised for Athletic from the spot, but David Selke has put Hertha back ahead.
38: Rausch comes on for the stricken Maroh as Arsenal prepare to take a free-kick. Elneny takes but it's cleared.
That will make it eight senior Köln players out injured. He's not even putting his weight on the affected leg as he's helped back round the pitch.
35: Another ball into the box from Arsenal that comes to nothing, Giroud unable to meet Welbeck's cross as he gets tangled up with Maroh. Bad news for Köln is their skipper (standing in for Hector) seems to have done his hamstring. He will have to come off. Rausch getting ready.
33: Decent move from Wilshere but Giroud is crowded out in the box. Welbeck then gets the ball on the edge of the box but he shoots across and wide.
He's never scored for Arsenal in 155 attempts, by the way.
30: Arsenal come close again. Giroud's cross finds Coquelin, and his shot goes out off the post. The much-derided Frenchman clearly has the greater attacking licence out of Arsenal's double pivot (with Elneny).
29: Maitland-Niles has been one of the brighter players, He crosses to Chambers, but his effort is straight at Timo Horn.
28: A chance for Osako, but he slips as he shoots and it goes out wide.
Elsewhere, Matthew Leckie has given Hertha BSC the lead away at Athletic Club. Still goalless in the other game in this group between BATE and Red Star.
26: Lukas Klünter looks to chase down a through ball, but Ospina is out to collect it first.
21: Decent cross from Maitland-Niles finds Wilshere, but he heads it straight at Timo Horn. Jannes Horn meanwhile requires a bit of treatment, but should be coming straight back on - indeed he does.
19: Arsenal move the ball forward swiftly. Giroud brings it into the but misses out as it finds its way to Horn.
17: Welbeck tries to orchestrate an attack on the left side of the pitch. The flag goes up against Maitland-Niles, yet the replay shows he was onside. Poor decision.
15: Elneny tries to find Chambers out on the right but it's too heavy and goes out for a goal-kick.
14: A couple of unlikely shooters for Arsenal. Chambers has his shot blocked, before Francis Coquelin fires wide from the rebound. A decent hit, to be fair.
12: Maitland-Niles is found by Elneny, but he's unable to beat the defender. Köln counter but their attack fizzles out as well.
11: All very sedate on the pitch at the moment, even the fans off it have quietened down. A bit.
6: Quick break for Köln, with Córdoba either shooting or crossing from the right. It could have caught out Ospina - again - but he gets a hand on it to put it wide. The Billy Goats can't do anything with the following corner.
2: An early attack from Arsenal. Welbeck and Jack Wilshere link up to find Maitland-Niles, with his shot put out for a corner by Timo Horn, who subsequently takes the corner from Mohamed Elneny.
1: After that, we're underway.
Before that, a moment's silence for Köln legend and FIFA World Cup winner Hans Schäfer, who died earlier in the month. In fact it's not silence, a minute's applause it is instead.
It's almost time for the match, with both sets of players coming out of the tunnel.
Arsenal captain Mertesacker is far from an automatic pick these days and plays for the first time in just under a month this evening. As Arsenal's Twitter account as pointed out, he in fact made his debut here for Hannover 96 in November 2003. He will retire at the end of the season to takeover as the head of Arsenal's academy.
Meré starts for the hosts as expected, whilst Jannes Horn (no relation to goalkeeper Timo Horn) starts at left wing-back and Yuya Osako makes up what could be a front three with Córdoba and Sehrou Guirassy.
Despite their injuries, there has still be room for Köln to make three changes from the Mainz game, of which only one is enforced. There's no Zoller of course is out (Bittencourt was only a sub on Saturday), whilst Konstantin Rausch and Matthias Lehmann drop to the bench.
It's a much more experienced team than, as Nelson, Matt Macey and Chris Willock all drop to the bench from that game, with Walcott injured. The only substitute with significantly more experience then those three is Alex Iwobi, who will thus surely feature later in the game.
Arsenal are as expected. They have made 11 changes from their win at the weekend, but just the four from the Red Star draw three weeks ago, with Ospina and Welbeck as predicated earlier, as well as Per Mertesacker and Calum Chambers all coming in.
Arsenal: (3-4-2-1) Ospina; Debuchy, Mertesacker, Holding; Chambers, Elneny, Coquelin, Maitland-Niles; Wilshere, Welbeck; Giroud.
Köln: (3-4-3) T. Horn; Sörensen, Maroh, Meré; Klünter, Özcan, Jojic, J. Horn; Córdoba, Osako, Guirassy.
The teams are in, and are as follows:
I’ll be back with the team news, which should be out around 5pm UK time/GMT ahead of the 6pm kick-off. In the meantime, take a look at our preview of the match.
The referee from Russia this evening is Vladislav Bezborodov, who has not taken charge of either side before. His assistants will be Valeri Danchenko and Maksim Gavrilin, the fourth official is Aleksei Lunev whilst the goal-line assistants will be Kirill Levnikov and Igor Fedotov. All are from Russia as well.
Jorge Meré, whose appearances for Köln have been limited by a hip problem, will join Dominic Maroh in defence, although according to Kicker this is as much to prepare for the weekend Bundesliga match against Hertha BSC, for which Frederik Sörensen is suspended.
They add to an injury list that already includes Germany international and Effzeh skipper Jonas Hector, Dominique Heintz, Marco Höger, Marcel Risse and Christian Clemens. Claudio Pizarro and Tim Handwerker are unregistered and are unavailable as well.
Köln are riddled with injury problems. Simon Zoller suffered a thigh injury in the defeat at Mainz and has been ruled out for the rest of 2017, whilst Leonardo Bittencourt tweaked his adductor during the week.
Olivier Giroud is likely to start as well, after missing out completely on the Spurs game through injury. Ospina will most likely be in goal, after missing the two games against Red Star due to a groin strain.
Theo Walcott is one senior player who has played in every match but he didn’t train on Wednesday due to illness and is not expected to be involved. That gives an opportunity to Danny Welbeck to return from a muscle strain that has kept him out for a month, with Wenger confirming he will start.
The good news for Köln is that none of that trio are likely to be involved, having been left out of Arsenal’s three following Europa League matches as Wenger has increasingly handed responsibility to youngsters like Reiss Nelson and Ainsley Maitland-Niles. The Arsenal boss said on Wednesday that the younger players who have appeared have “done extremely well.”
Once the match got underway, Jhón Córdoba lobbed David Ospina to give the Billy Goats the lead, but a change of shape from Arsène Wenger at half-time led to goals from Sead Kolasinac, Alexis Sánchez and Héctor Bellerín to win the match for the Gunners.
Arsenal won the meeting between these two sides at the start of the campaign. The game will be best remembered for the invasion of an estimated 25,000 Köln fans on Germany, with only a fraction having officially-allocated tickets. The subsequent chaos led to the game being delayed by an hour and earned Köln a €60,000 fine.
Since the win against BATE, they’ve lost 3-0 to TSG 1899 Hoffenheim and 1-0 on Saturday away at 1. FSV Mainz 05. Arsenal on the other hand bounced back from their defeat to Manchester City before the international break by beating North London rivals Tottenham Hotspur 2-0 on Saturday lunchtime, boosting the morale of the Gunners support until the next defeat!
They need to beat Arsenal though to realistically keep those hopes alive. If they get a draw they will need BATE to get something against Red Star in the other game, although a draw between those two sides would – just – keep Köln alive even if they lose.
Köln’s euphoric 5-2 victory over BATE Borisov on matchday four might not have been enough to inspire their domestic form – they are still without a win in the Bundesliga – but it gives them a chance of reaching the last-32 of this competition.
Arsenal are already assured of their place in the knockout rounds, despite a highly-uninspiring goalless draw with Red Star Belgrade in their previous match. Thanks to their superior head-to-head with the Serbians, a draw is all they need to secure top spot in Group H.
Good evening and welcome to VAVEL UK’s coverage of the UEFA Europa League match between 1. FC Köln and Arsenal, at what is set to be a raucous RheinEnergieStadion. I’m James Rees and I will be keeping you up-to-date this evening.