Full-time: Man United open their pre-season with a 1-1 draw. Nothing hugely entertaining, but a massively young team in the second half, with impressive displays from Chong and Joel Pereira in goal. Mourinho will have learnt some things about his side, and about his youngsters.
85' Substitution for United sees Tuanzebe and Gomes come on. That's nine academy players who have been involved today. And it also means United's front three is Gomes, Greenwood and Chong, with a total age of 51 and an average age of 17.
82' Chong has been brilliant so far. No fear, creativity, persistence, pace. United fans love him already. He's been great, and he will have put himself in the mind of Jose Mourinho for the opening game of the season against Leicester already.
77' Goal! Man United level late on, with a goal of chaos. Chong does brilliantly on the right flank, crosses in beautifully. Herrera's header is saved, the ball then hits the post, and finally falls to Juan Mata who finishes.
75' Substitution for Man United: 16-year-old (yes, you read that correctly) Mason Greenwood has come on for Manchester United's first team to replace Luke Shaw. A really brilliant moment for the local lad who was stunningly good for United's under-18s side last season, scoring at a rate of often over a goal a game.
68' You know it hasn't been a completely enticing game... the Mexican Wave is out. At least there are some actual Mexicans doing it given there are plenty of Club America supporters inside the ground.
65' Chong gets on the ball for the first time. There's an excitement, and it's because he can pull a variety of things off and has the low centre of gravity that allows sudden acceleration. He tries to feed through Luke Shaw and comes very close to succeeding, but the Club America centre-back cuts it out.
62' So, Tahith Chong makes his debut for United, an uncompetitive one albeit. The former-Feyenoord man has been scintillating in the youth sides. He did fantastically well to return from a tough injury which required surgery and months on the sidelines. He came back, was promoted to Ricky Sbragia's under-23s and instantly impressed despite the step-up in challenge. Chong's footwork allows him to weave through defenders, and his intelligence has shown, too. With an even bigger afro than Fellaini, he's not a hard one to spot.
60' Substitutions for Man United: Matteo Darmian and Tahith Chong replace Anthony Martial and Demi Mitchell.
58' Goal! Club America take the lead with a bullet header from Martin. A free header that left Joel Pereira with no chance of stopping it. A fantastic header from the America man, but poor marking from United's defence.
56' Club America are making more substitutions. Roger Martinez is one of those coming off, and United will be happy about that. He's been one of America's biggest threats throughout.
52' Good save from Joel Pereira only a few minutes after coming on. He denies Martinez with a strong hand, making himself big. Andreas Pereira, too, helped out, covering the space in which Martinez could have shot alternatively and so forcing the striker's hand.
51' Luke Shaw brings the ball out of defence for United after another chance for Club America. United are looking sloppy, and America are looking threatening.
46' So, hopefully we've avoided the age old tradition of pre-season games having a 15-minute dull period at the start of the second-half because there's been 11 changes on either side. Only one outfield change for United (in Fosu-Mensah) and Mourinho is clearly looking to test his players and keep the flow of the side.
45' Kick-off: Back underway in Phoenix, and not too many changes for United. Club America have made five changes, including bringing on one player with the number 286 on the back of his shirt. I won't bore you with the specifics of their changes.
04:03 Substitutions for Man United: Joel Pereira replaces Lee Grant, Fosu-Mensah replaces Valencia at right-back. It looks like that's the only changes for United, despite it being their first game of pre-season.
04:01 Looks like Martial, Bailly, Mata, Mitchell Shaw and Pereira are staying on as they come out in their kit. But there will be a few changes, with Lee Grant set to be replaced by Joel Pereira in goal. Timothy Fosu-Mensah is stripped and will come on, possibly for Antonio Valencia.
03:59 Man United's official TV channel showing highlights of the club's 2008 rout against West Brom at home with goals from Rooney, Ronaldo, Berbatov and Nani. I'm not quite sure to what extent United fans want to see that in comparison to their current success and style of football.
03:53 United fans could view that first half of pre-season in very different ways if they want to. It's been a decent first half for the optimists in the fanbase. For those less positive, it's been nothing different from last season, it's been pretty unexciting and United's finishing has still looked poor. Either way, it's only 45 minutes and it's the first game of pre-season, so both responses are premature at this stage.
Half-time: Man United's first 45 minutes of pre-season and manager Mourinho will be relatively pleased with that. It tailed out towards the end, but United started with good pace. Shaw and Martial have looked lively if not completely effective yet. Bailly has been impressive and Grant has been solid when called upon. Andreas Pereira, playing as a No. 6, has shown his potential contribution to the side with his vertical passes from deep.
44' Martial earns United a free-kick. The Reds have three great set piece takers in Pereira, Mata and Martial. The latter takes it (he's been practising hard in training) and it rises just over and curls just wide of the right post.
41' United have tailed off in this first half. Unsurprisingly, given it's their first game. Club America, alternatively, are playing their final game of pre-season before they get their campaign underway, and it shows. They've grown in confidence and strength. United have done little over the last 15 minutes.
39' Brilliant from Eric Bailly. Uses his body, footwork, pace and strength fantastically to escape an awkward situation. Examples like this are why United fans were so baffled to see him play so little last season.
38' It's a third consecutive corner for Club America in quick succession. In all three, United haven't dealt with them instantly. A free header in the final one, but it's headed well over.
36' Corner for Club America after a huge looping deflection off a shot. McTominay is forced to go to ground to make the challenge as the ball falls to Rodriguez.
33' Impressive from Grant. Martinez powers through the United defence despite it looking like an impossible task. United give the ball away just inside their own half and don't recover properly, Martinez fires a strong shot that stings the gloves of Grant, and the new signing is quick on his toes to pounce on the loose ball in the box and stop the Club America forward from tapping home the second opportunity.
31' Ibarguen fires well over for Club America. He earned himself space to shoot impressively, though, with a nice stop-start trick to evade the attention of his defender. His strike is nowhere near Lee Grant's goal.
26' Lee Grant makes his first major stop in a United shirt. Club America are building up patiently. They cut back just before reaching the byline to evade the attention of the United defender and drag it back, where the finish forces Grant to parry it away with an outstretched right-hand. United's defence clears the rest up.
23' Shaw has already put himself through a pre-pre-season in Dubai with United's Head of Fitness. The young Englishman is having his final chance to prove himself to Mourinho and United fans, and he's going for it. He did something similar before the 2015/16 season and started that campaign in storming form. A double leg break interrupted that season, but he'll be hoping he can avoid that or any other injuries. The World Cup and Ashley Young's success with England, reaching the semi-final, gives Shaw the chance to start the season as the first-choice left-back.
22' United have looked fine in defence so far. This looks set to be the back four that starts the Premier League season on Friday, August 10th. Valencia at right-back captains the side with Bailly and Smalling centrally and Shaw on the left.
20' Chances for both Shaw, running through with pace and playing the one-two, and Martial, seeing his shot deflected for a corner. Andreas Pereira is on corner duties but so far, they've come to nothing.
14' Mata hits the post! Firing without too much power across the grass, the Spaniard drags his shot just onto the right post of the Club America goal. Martial made that chance with a forceful run inside from the left flank before cutting it back for Mata just on the edge of the area. That's the closest United have come.
12' Martial has had a busy start, and this time he's laid off by Herrera. He fires over. Demi Mitchell showed good composure in the penalty area there, electing not to shoot and waste the chance, keeping the ball and offloading to Herrera.
9' Martial goes down in the box, now. A cross from the right flank comes in and Martial tries to take it into his body and turn all with his first touch. The Frenchmen goes down and claims for a penalty, but the referee gives only a corner, which comes to nothing.
8' Martial showing great hold-up play to keep possession in United's hands. His teammates need to be quicker to support him.
6' United almost have their first chance through Demi Mitchell, the young versatile academy graduate who has been playing predominantly as a left-back in the youth sides for the last couple of years. He's fed through but the Club America defender just managers to hook away the ball and deny Mitchell the opportunity to run clear through on goal.
5' Pereira is playing very deep within that midfield three, dropping just in front of the two defenders and bringing the ball up the field with him, with the help of Mata and Herrera.
4' No lethargic start for United. Pereira is pressing, Martial looks on his toes with a few runs off the shoulder of the defender already, and United have started in good fashion.
03:00 Kick-off: We're underway in the University of Phoenix Stadium in Arizona, USA. United are wearing their new kit, with red shirts, black shorts and red socks. United fans will know that's a change from their usual strip of red shirts, white shorts and black socks. Controversial. The Reds kick-off to get their pre-season begun.
02:58 The big stories from that starting line-up: A debut for Lee Grant after his move from Stoke City, a chance for Andreas Pereira to try and start proving himself in a United shirt after two seasons away on loan in La Liga, a chance for the numerous academy graduates on the substitutes bench to make a name for themselves off the bench at some point in this game.
02:57 Man Utd starting XI vs Club America: Grant; Valencia, Bailly, Smalling, Shaw; Herrera, McTominay; Pereira, Mitchell, Mata; Martial.
Team news will be out at around 2AM BST, so continue following along with VAVEL UK until then for build-up for the return of Manchester United. Alternatively, go get some sleep and come back at 2:45AM to follow our live feed and keep up to date.
Chong's positional awareness is impressive, and that's allowed him to play across the front line, including as a striker very briefly, for Ricky Sbragia's reserves side. Kieran McKenna has just joined Mourinho's coaching set-up, promoted from his position as under-18s manager. He'll know how to manage Chong, having supported him through surgery in 2017 that left him on the sidelines for some months. McKenna's presence will be a huge help to the youngsters in the USA on tour with United.
While the other youngsters on the trip will get some game-time, Chong is the most likely to start tonight, due to United's lack of forwards on tour. Chong is easily recognisable with his bouncing afro, even larger than Fellaini's. His footwork, though, is magnificently good and the balance and agility in his locker means he can weave past player after player with relative ease.
The two names sticking out there would be new signing Lee Grant, brought in from Stoke City on a free transfer to be United's third-choice goalkeeper, allowing young talent Joel Pereira to go out on loan this season. The second in Tahith Chong, the young academy product, signed from Feyernoord a few years ago, who has overcome serious surgery to be the standout of United's reserves side.
United's likely starting XI today, then, will be: Grant; Valencia, Smalling, Bailly, Shaw; Herrera, McTominay, Pereira; Mata, Martial, Chong.
On Alexis Sanchez's situation, Mourinho was glum, too. "If Alexis is not working with us for 15 to 20 days, it will be very bad,” Mourinho explained. “I know the club is making the effort. I have to respect the US authorities in their process and selection of visas. Hopefully he can come and join us later, because it will be important to work with him.”
“Pre-season is very bad, I have to say that," Mourinho said, in a press conference in which he looked downbeat throughout despite it being the first of the season. "The only positive thing of pre-season is for the young boys that have a fantastic opportunity to train with us and know what it is to be a Manchester United first team player."
Other key players like Nemanja Matic and David de Gea will not join up with Mourinho and his squad until next week. Mourinho is worried.
Furthermore, United's two major new signings, midfielder Fred and young full-back Diogo Dalot, are injured. Dalot will be able to make his debut only in September, Mourinho told reporters on Wednesday, while Fred is fit but has been at the World Cup with Brazil and so won't join up with United for some time yet.
But wholesale changes will mean Mourinho will be forced to bring on a number of young players. Nine players in United's squad will miss the whole of the trip to the USA, including all those who were in Gareth Southgate's England team, and Romelu Lukaku and Marouane Fellaini of Belgium, Paul Pogba of France. Alexis Sanchez, meanwhile, remains in Manchester after his application for a US visa was rejected because of a suspended sentence he was handed in Spain for tax fraud.
In 2015, Morgan Schneiderlin, scored a debut goal to give United a 1-0 win. Games this early on in pre-season are usually dull affairs compared to those later on in tours. The heat in the University of Phoenix Stadium won't help with that, and play could look lethargic at times. Expect wholesale changes at half-time since it's the first game, as well.
United have faced Club America on a few occasions, with the Mexican side becoming a fairly regular opposition during the club's pre-season tours of the USA. Under Sir Alex Ferguson and some of his successors, United visited China and South Africa as well as Australia. The USA is the only destination for the Reds these days.
Club America are from Mexico City, Mexico and compete in the country's Liga MX. Las Águilas have won the joint-most league titles in Mexico, and have dominated football for many years south of the US border.
Man United have travelled to the USA without all of their players who were involved at the World Cup. That means tonight's game is an opportunity for the youth players and fringe players of the side to make an impression on Mourinho, even though the opposition is not one of Europe's heavyweights, but rather Club America.
It's been five days since Manchester United's Paul Pogba lifted the World Cup for France in Russia after a 4-2 victory against Croatia. Only five days, but now his teammates are set to face their first test of pre-season in the USA in preparation for a vitally important season where Jose Mourinho must prove he can catch Pep Guardiola and Manchester City.