Debutant goalkeeper Lee Grant made a couple of important first-half saves but there was nothing that his replacement Joel Pereria could do with Hector Martin's thumping 59th-minute header into the top corner.
Mata ensured that United's pre-season preparations would not begin with a defeat when he squeezed a 15-yard shot through goalkeeper Oscar Jimenez, after Ander Herrera's header had come back off the post.
Relive how the action unfolded at the University of Phoenix Stadium with Sports Mole's minute-by-minute updates below.
02.00amIn three weeks' time, Manchester United kick off the Premier League campaign when they host Leicester City at Old Trafford. Tonight, Jose Mourinho's men kick off their pre-season tour of the United States with a friendly against Mexico's Club America, and Sports Mole has every minute covered...
02.06amWith all of his World Cup contingent enjoying a brief summe break and Alexis Sanchez yet to fly out to the States because of visa complications, Mourinho names just about as strong a lineup as he possibly could from his travelling party with some exciting young talent in reserve for the second half.
02.08amIn the absence of Romelu Lukaku and Marcus Rashford, Anthony Martial deputises up front for the Red Devils. The Frenchman has reportedly told United officials that he wants to leave the club this summer because of a lack of starting opportunities which caused him to miss France's World Cup triumph. He has been heavily tipped to join Tottenham but for now the 22-year-old remains a United player.
02.10amIt was the signing of Sanchez last January which seemed to signal the beginning of the end for Martial at Old Trafford. Alexis could not fly out with his United teammates to America because of visa complications but has now been given permission to join up with the rest of the squad.
02.12amSpeaking to United's official website about the Sanchez situation, Mourinho gave an insight into Martial's future at the club, and it does appear as though the pacey forward is in his plans...
Mourinho said: Hopefully, he [Sanchez] can at least join us later because it is important to work with Juan Mata, Alexis and Anthony Martial, who we think are the players we have for the start of the season. There is no Lukaku, Rashford or [Jesse] Lingard."
02.14amAnother player who is reaching make-or-break time at Old Trafford is Luke Shaw, who has reportedly turned up to pre-season in excellent condition and is in line to be given the opportunity to nail down United's left-back slot. If he is over his fitness issues then there really is nothing stopping the lad.
02.16amShaw has told United's official website that he is determined to finally prove himself at the club.
He said: "I want to try to prove to the manager that I can be in his team, and not just for these games...when everyone comes back and everyone is fit and ready, I still want to be one of the first names on the team-sheet. It's time for me to show him over the next few weeks in particular what I can do and why I deserve to be in his team."
02.18amThe former Southampton academy graduate was once hailed as the next big thing in English football - he was the most expensive teenager ever when he joined United for £27m in 2014 - but Mourinho has continually sidelined him in favour of other options and has publically criticised Shaw several times.
02.20amAnother United defender who may feel that he has something to prove is Chris Smalling, who was omitted from Gareth Southgate's England squad despite being the only English centre-back playing regularly at a top-six club. It must be said, the performances of John Stones and Harry Maguire vindicated Southgate's decision but there is a way back for Smalling if he maintains his club form from the back end of last year.
02.22amBehind Smalling, 35-year-old Lee Grant must be pinching himself, having swapped the bench at relegated Stoke City for a gig at the biggest club in English football. Third-choice stopper Grant makes his United debut today with David de Gea on his holidays and Sergio Romero injured.
02.24amThe arrival of Grant means that Joel Pereira will go out on loan for the 2018-19 season.
Mourinho confirmed as much to United's official website, saying: "Joel is a Manchester United goalkeeper but, two years without football, he has to play. Joel is here with us. It's good for him to play but then he will go on loan"
02.26amThe goalkeeper's namesake Andreas Pereria has recently returned from his own loan spell at Valencia, where he scored just once in 29 appearances. The 22-year-old has his work cut out to make the grade at Old Trafford, and that starts tonight alongside Ander Herrera and Scott McTominay in midfield.
02.28amAlongside Smalling, captain Antonio Valencia and Juan Mata are the most established first teamers in United's starting lineup. Between them they made 88 Premier League appearances last season, which is more than everybody else in the current touring squad combined.
02.30amUnited supporters will be hoping that Eric Bailly can finally overcome his injury problems and join those ranks of first-team regulars this season. The Ivory Coast international is the club's most complete centre-back but has been in and out of the side so has yet to reach his true potential.
02.32amIf you are to believe widespread reports, Mourinho is active in the transfer market for a new defensive partner for Bailly. Daley Blind has gone and none of Smalling, Phil Jones and Marcos Rojo have convinced over long periods. Tottenham's Toby Alderweired and Leicester's Harry Maguire are top targets.
02.34amAs it stands, United's only outfield signings this summer are defensive midfielder Fred from Shakhtar Donetsk and right-back Diogo Dolot from Porto. Fred is soon to join up with the squad in America while 19-year-old Dolot is in the States but is not expected to play until September because of an ankle knock.
02.36amWhere else may Mourinho be looking to strengthen this summer? Left-back has long been an area of concern for the Red Devils but there interest in Danny Rose appears to have waned with Shaw's return to fitness. A superstar attacker? Moves for Gareth Bale and Antoine Griezmann are off the table.
02.38amDo United have a superstar attacker already coming through their ranks? Sixteen-year-old Mason Greenwood, who scored 17 goals in 17 starts for the Under-18s last year, is on the bench today.
02.40amGreenwood had been touted for a start as the central striker today with Martial occupying a wide-left position. However that role has gone to Demetri Mitchell, a left-back by trade who spent last season on loan at Hearts. He has one previous Premier League appearance to his name for United.
02.42amUnited may be without many of their top players for this tour but there was certainly some star power on show at the training base this week as Winston Churchill himself, Gary Oldman, made an appearance.
02.46amA little bit of info on Club America, who are the joint-most successful team in Mexican football history with 12 league titles and finished second in their domestic competition last year.
02.48amThe team from Mexico City are at the other end of their pre-season regime, having been playing friendlies across the States the past month. Their domestic season actually starts next week.
02.50amClub America are also missing a couple of their own World Cup stars, including Mexico striker Oribe Peralta and Colombia's Mateus Uribe, who hit the crossbar in their shootout defeat to England. Defender Edson Alvarez is back for a run out having been part of Mexico's squad at the World Cup but former Paris Saint-Germain winger Jeremy Menez is out having suffered a serious pre-season injury.
02.52amHEAD TO HEAD: United have faced Club America twice before - beating them 1-0 in a friendly in 2015 courtesy of a debut goal from Morgan Schneiderlin - it didn't get much better for the Frenchman. The Red Devils won the other encounter in 2003 with Ruud van Nistelrooy among the scorers.
02.54amThe Mexicans may have a fitness advantage today as they are a month ahead in their pre-season preparations, and also an advantage when it comes to the conditions. It is a scorching 40 degrees in Phoenix, Arizona, with the players protected a little from the heat by the stadium roof.
02.56amNo Paul Pogba tonight of course with the World Cup winner still busy celebrating. Check out this Pogba goal video United plucked from the archives yesterday. And they let him go, why?
02.58amPREDICTION: Friendlies are always difficult to predict and often the result is sacrificed in favour of fitness and opportunity. But Mourinho is a winner and he will want to start United's tour off with a victory. I don't think they will have it all their own way though - 1-1 draw final score.
1 minKICKOFF: We are underway in Phoenix with the American fans out in force...
3 minMitchell knocks in a cross which Martial can't quite bring under control at hip height.
5 minAndreas Pereira has started in a very deep role, dropping in between the two centre-backs to pick up the ball. The 22-year-old started as an attacking midfielder but has slowely moved backwards and today it is very evident that McTominay and Herrera are playing ahead of him in the three.
7 minThe Mexicans have made a decent start with Colombian left winger Andres Ibarguen showing his pacey and direct running on a couple of occasions. His compatriot Roger Martinez is another danger man up front but he has yet to get involved in the game under the watchful eye of Bailly.
9 minUnited want a penalty after Martial is felled in the box, with captain Paul Aguilar the Club America defender under the spotlight. There was a bit of a tangle as Martial tried to turn away from the Mexico international but the referee showed no interest, and the Frenchman had few complaints.
11 minIbarguen bursts into the box but Valencia, who is starting his 10th pre-season at United, has the speed to keep up with the winger and ushers the ball behind for a goal kick.
13 minSHOT! United work the ball nicely down the left and Herrera feeds Martial who bends a shot just wide of the post. It was the type of right-footed curling finish that Martial excels at but he could not get enough whip on his 20-yard effort this time.
15 minOFF THE POST! This time Mata has a shot himself and it skids off the surface and back off the post. Goalkeeper Agustin Marchesin is beaten and gets lucky that the rebound falls to his own defender.
17 minShaw makes his first notable venture forward and Mata tries to find him with an incisive through-ball. Marchesin comes off his line to claim the ball and is happy to accept Shaw's handshake after the left-back caught the goalkeeper with a dangling foot.
19 minSmalling makes an important clearance to stop Ibarra's pass from reaching Martinez.
21 minThe Red Devils have wrestled control of possession now, having shared it equally with the Mexicans in the opening 10 minutes. Pereira is dictating the play from the base of the midfield - a role that United need filling after Michael Carrick's retirement. Could he be an unlikely solution for Mourinho?
23 minCLOSE! Martial picks up the ball in the left channel and drives forward, cutting inside and unleashing a shot which takes a couple of deflections on its way narrowly wide, the second off goalkeeper Marchesin who was wary of the ball sneaking into the bottom corner.
25 minIt has been a very assured start from Bailly, who is a formidable one-on-one opponent and has given Martinez no change so far. The 24-year-old was Mourinho's first signing as United manager so you would think he remains central to his plans if fit.
28 minSAVE! Lee Grant has has first save to make as a Manchester United goalkeeper, getting a strong left hand down to push away a shot from right-back Aguilar, who had found himself in an unfamiliar advanced position. Valencia swings his foot through the subsequent clearance.
30 minSHOT! Ibarguen continues to be lively without much end product. Ibarra drifts in from the right and switches the play to his teammate, who fires high and wide with a wild left-footed shot from 25 yards.
32 minAside from the Colombian winger, the standout player for Club America has been their World Cup centre-back Alvarez, who is very mobile and composed on the ball, unphased by Martial's speed. At 20 years old it appears as though the defender has a bright future.
34 minSAVE! This is a good spell from the Mexicans and Grant is called into action again. Martinez bulldozes his way through Shaw and Bailly to rifle a 15-yard shot straight at Grant, who can't hold the powerful initial effort but reacts very quickly to throw himself on the loose ball.
36 minClub America are growing in confidence, evidenced by midfielder Corona embarking on a run down the flank which earns his side a corner.
38 minCHANCE! The Mexicans have a series of corners and waste a decent free header when Rodriguez nods over the crossbar.
40 minSilky defending from Bailly who follows his man to the byline before lifting the ball over him and running out of defence to ease the pressure on his side. Mourinho must be really pleased with what he has seen from the Ivorian so far.
42 minMourinho's overall half-time report will be mixed. Yes of course this is pre-season and United are missing a lot of players but he may have hoped to have created a few more chances.
44 minUnited's most fluid move of the half ends with Martial felled 30 yards from goal. Mata tries to take a quick free kick which is saved by Marchesin, and the referee calls the play back. Martial steps up to have a go but his shot - high and wide to the right - was never threatening.
3.52amA solid but unspectacular start to United's US tour as the referee calls time on an even first half. There have been a couple of chances at either end with Juan Mata going closest when hitting the post.
3.54amThe biggest positives for Mourinho so far have been the performance of Eric Bailly, and the fact that this has been a competitive fixture. We've seen Everton run out 22-0 winners this summer and that sort of circus doesn't help anyone. Club America are game and United will do well to win from here.
3.56amThe Mexicans would have been in front already had it not been for a couple of decent saves from debutant Lee Grant. The former Stoke and Derby stopper kept out both Aguilar and Martinez in the latter stages of the half.
3.58amMourinho may want to take inspiration from this man for his half-time team talk...
4.00amThere was plenty of warm-up activity on the pitch at the break and I'm sure we will see a dozen or more substitutions in the second period. Timothy Fosu-Mensah is going through the most rigorous routine of the United lot.
4.02amSUBSTITUTIONS: Mourinho is going to make two changes now, and I'm sure more will follow. Fosu-Mensah, who made 24 appearances on loan at Crystal Palace last season, is on for Valencia and Joel Pereira has replaced Grant in goal.
46 minKICKOFF: We are back underway in Phoenix. Club America have made five changes - I'll try to detail those as the half wears on.
48 minOne of the Club America new boys is wearing the shirt number 286. The game's gone.
50 minIbarguen, Club America's main threat in the first half, is one of those who have made way, as well as Rodriguez, Emanuel Aguilera. Pedro Arce, Oswaldo Leon and Carlos Vargas are on. That's what I've figured out so far.
52 minSAVE! Joel Pereira is off his line and stays tall to block from Martinez, who had been slipped through and brought the ball under control well. United need to be careful here, only a last-ditch block from Smalling had kept them on level terms moments earlier.
54 minClub America are regularly finding pockets between the United defence and midfield, which could be down to a lack of recognised holding player in the Red Devils XI. Mourinho seems keen to bed that system in with Pogba in mind, but Andreas Pereira isn't suited to such a deep role.
56 minMata floats a cross towards Martial who had made a decent run between the Club America centre-backs, but 19-year-old Vargas cuts out the ball before it can reach the Frenchman.
58 minSUBSTITUTIONS: Club America make another two changes with Reyes and Martinez, who has been a nuisance, making way for youngsters Ulises Torres and Francisco Gonzalez.
59 minUnited are behind courtesy of a bullet header from Martin. Smalling and Bailly allow the attacking midfielder to ghost into space and he powers a thumping header past Pereira and into the top corner.
61 minSUBSTITUTIONS: Mourinho was planning a couple of changes before the goal and has gone ahead with those. Tahith Chong and Matteo Darmian are on for Mitchell and Martial.
63 minCLOSE! The ball drops to Shaw, who has been pushed upfield as part of United's reshuffle, and he very nearly strokes a right-footed shot into the bottom corner after it broke to him 20 yards out.
65 minDarmian has gone in at left-back, with Shaw ahead of him on the wing and 18-year-old Dutchman Chong on the right. Mata is playing through the middle as a sort of false nine. A few square pegs there...
67 minSUBSTITUTION: Club America's goalscorer Martin comes off with another youngster Brandon Garcia getting a run out. I make that eight changes from the Mexicans so far.
69 minThe removal of Martial perhaps highlights that Mourinho isn't too fussed about the result tonight. This is a proper friendly by name - United's pre-season goes up a notch when they play in the International Champions Cup in a week's time.
71 minSUBSTITUTION: And now a change of goalkeeper from the Mexicans as Oscar Jimenez replaces Marchesin. Will we see more United changes? What about 16-year-old Mason Greenwood?
73 minYELLOW CARD! You don't see many yellow cards in friendlies but the American referee there didn't have much choice for a blatant drag back from Shaw.
75 minSUBSTITUTION: Here he is, 16-year-old Mason Greenwood, born in October 2001, on for his first-team Manchester United debut. Luke Shaw is off with 75 valuable minutes under his belt.
78 minUnited grab an equaliser and it comes from the makeshift striker Mata. Chong checks back onto his left foot and whips in a deep cross which Herrera heads against the post. A miscued clearance falls to Mata who squeezes the ball through several bodies and over the line. The goalkeeper should do better.
80 minThe Red Devils are pushing for a winner now and Chong has been the catalyst. His giant afro makes him stand out in appearance and his performance so far has been pretty stand out too.
82 minAndreas Pereira wastes a decent free kick opportunity by knocking it down the goalkeeper's throat.
84 minThe impetus is fully with United, but not so much so that Scott McTominay can pull off the overhead trick he just tried. The midfielder's efforts to copy a United legend who has recently moved this side of the pond unsurprisingly fall short.
86 minAnd now the Scotland international is down with what appears to be a head injury. Hopefully nothing more serious than a bruised ego.
88 minSUBSTITUTIONS: Mourinho isn't going to take any chances with McTominay, bringing on Axel Tuanzebe to sit in midfield. The highly-rated Angel Gomes is on for Mata as well for the final few minutes.
90 minUnited now have a front three of 18-year-old Chong, 17-year-old Gomes and 16-year-old Greenwood. Class of 2018?
90+2 minThe Red Devils don't seem too fussed about pushing for a winner and are largely playing keep ball in stoppage time.
04.56amUnited's US tour begins with a draw as Juan Mata's equaliser salvages Mourinho's men a 1-1 scoreline. Some positives for the Red Devils - Eric Bailly, Luke Shaw and teenage substitute Tahith Chong. Onto Sunday when they face the San Jose Earthquakes, before AC Milan come to town next week.
04.58amThat concludes our coverage from the University of Phoenix Stadium. You can read our match report on the action here. Thanks for joining me for this one - wherever you are in the world but especially you nightowls in the UK! Until next time, goodbye!