The Red Devils gave a huge boost to their hopes of finishing inside the Champions League places with a third straight Premier League win.
Erik ten Hag's side took the lead through Rasmus Hojlund who netted for the fifth game in a row in the league.
Douglas Luiz then hit back and turned the momentum to the hosts as they piled on the pressure trying to find a winner.
But United defended well and then struck at the other end through McTominay whose header reduced the gap between the two teams to five points.
Today, 19:15By Jack Johnson
Aston Villa 1-2 Man United: REACTION
That's all for our live coverage of Man United's 2-1 win against Aston Villa!
The Red Devils dug deep to steal a late winner through Scott McTominay and boost their Champions League hopes.
You can read more reaction to the game below...
Hojlund ushered off pitch after gesture at Villa fans before making young supporter's day
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Today, 19:09By Jack Johnson
Aston Villa 1-2 Man United: REACTION
Man United have now won four consecutive away games in all competitions.
That is their longest such run on the road since winning 10 in a row from June to October 2020.
The Red Devils are finally hitting form after a rough campaign so far under Erik ten Hag!
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Today, 19:04By Jack Johnson
Aston Villa 1-2 Man United: REACTION
Erik ten Hag has also commented on Luke Shaw who was substituted at half-time for Victor Lindelof.
He explained: "Precaution. He had some complaints and we can't take any risks with him because he's had any injuries in the past.
"We'll have to see how it goes in the next few days. It's not an advantage to lose him, everyone knows my philosophy to have left-footers at left centre-back and left-back.
"We have to make compromises and it is not to our advantage."
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Today, 18:58By Jack Johnson
Aston Villa 1-2 Man United: REACTION
Erik ten Hag is delighted with his side's crucial three points.
"It is a massive win for us," the Man United boss told Sky Sports.
"We've got closer and that was the aim for today. That was absolutely our target and we've done it.
"The way we did it, I liked it. I especially liked the first 20 minutes when we controlled the game.
"At 1-1 we had to fight back and we are really happy for today.
"It was so open and it could go two ways but we found the mentality and character to win the game. The subs also had an impact.
"Scott [McTominay] is great. He can score many goals. He's always coming into positions to score goals.
"We knew Scott would get into the box and can score goals."
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Today, 18:53By Jack Johnson
Aston Villa 1-2 Man United: REACTION
Man United legend Rio Ferdinand takes aim at Douglas Luiz for his celebration after his equaliser.
The Brazilian shimmied in front of his fans after scoring but the Red Devils went on to grab a late winner...
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Today, 18:49By Jack Johnson
Aston Villa 1-2 Man United: REACTION
Harry Maguire has also given his thoughts on the win.
He said: "I think we started well, scored to deservedly lead and then the tempo of our pressing dropped off and we weren't aggressive enough.
"We allowed them back in and we conceded from a set-play which really disappointing at a place like this.
"Great spirit and fight to come back and Scott [McTominay] is the match-winner again. It's an amazing feeling but we'd like to make it a little more easy for ourselves.
"Scott has come on in numerous games this year and made the difference for us.
"We had to dig deep in the second half think we did in the end and deserved the win."
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Today, 18:43By Jack Johnson
Aston Villa 1-2 Man United: REACTION
Winning goalscorer Scott McTominay has reacted to a crucial win for Man United this evening.
McTominay told Sky Sports: "We started really well, but they are a really good team and came back into it and caused us problems.
"The guys at the back were immense, particularly Harry [Maguire] and Raphael [Varane]. It was a top-level performance and a deserved win in the end.
"Every game you win is massive for taking a step forward and confidence for the boys.
"It is all positive but it is about repeating it and not getting too far ahead of ourselves when we win a few."
Speaking about his goal, he said: "It was an unbelievable cross to be fair, whipped with a lot of pace. I just needed it to hit my head and get it on target.
"Full credit to the boys, we created a lot of good chances which may go unnoticed."
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Today, 18:38By Jack Johnson
Aston Villa 1-2 Man United: REACTION
Scott McTominay has scored more goals in the Premier League this season than in his previous three campaigns combined (6).
His four goals as a sub are the joint-most in the competition this term (also four by João Pedro).
The man for the big occasion!
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Today, 18:36By Jack Johnson
Aston Villa 1-2 Man United: REACTION
The gap between Man United and Aston Villa is reduced to five points thanks to Scott McTominay's late winner.
Erik ten Hag's side have given a massive boost to their chances of finishing in the Champions League places.
Anything but a win at Villa Park would have left them a long way away from their goal!
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Today, 18:32By Jack Johnson
Aston Villa 1-2 Man United: FULL TIME
MAN UNITED HAVE WON IT!
That is a huge win for the visitors! McTominay's head sees them pick up a crucial three points!
Villa have now lost three straight home games while the Red Devils are up to three wins in a row!
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Today, 18:27By Jack Johnson
Aston Villa 1-2 Man United
90+5' United are defending well here.
The hosts haven't had a chance since conceding.
Ten Hag's men look to be holding onto a crucial three points.
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Today, 18:24By Jack Johnson
Aston Villa 1-2 Man United
90+2' Hojlund comes off for United.
He shows the 2-1 scoreline to the home fans as he walks off.
Mainoo is off too as Evans and Amrabat come on.
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Today, 18:23By Jack Johnson
Aston Villa 1-2 Man United
90+1' We're into SIX minutes of added time.
United will be trying to hold on now and see this out.
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Today, 18:22By Jack Johnson
Aston Villa 1-2 Man United
88' How big could that goal be for Man United?
Their Champions League hopes may have just been saved!
Aston Villa has responded with a double change as Digne and Zaniolo come on for Moreno and McGinn.
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Today, 18:20By Jack Johnson
GOAL! Aston Villa 1-2 Man United: Scott McTominay
86' UNITED HAVE TAKEN THE LEAD AGAIN!
MCTOMINAY HEADS HOME SUPERBLY!
Dalot's whipped cross is perfectly into McTominay who beats Cash to the ball and heads home!
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Today, 18:17By Jack Johnson
Aston Villa 1-1 Man United
84' Can either side find a winner here?
It looked as if Villa were destined to score as they piled on the pressure 10 minutes ago.
But they've lost their control and United are now dominating possession and hoping for a winner.
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Today, 18:15By Jack Johnson
Aston Villa 1-1 Man United
82' Garnacho's shot is saved easily by Martinez.
United finally break through Villa's press with some neat build-up but the winger can't take advantage.
The hosts' momentum seems to have been sapped and the atmosphere has gone quiet...
Are Villa happy with a point here?
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Today, 18:12By Jack Johnson
Aston Villa 1-1 Man United
80' Diaby wastes a great chance for Villa!
He receives the ball down the right from McGinn and charges into the box!
But he decides to slow down and cut inside which allows Lindeolf to recover and Maguire to get across and block!
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Today, 18:10By Jack Johnson
Aston Villa 1-1 Man United
78' United are trying to slow the game down.
It's working at the moment and they may feel they need to regain control and win this game.
The draw is a better result for Villa.
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Today, 18:08By Jack Johnson
Aston Villa 1-1 Man United
76' Luiz's goal has Villa Park bouncing!
We're into the final 15 minutes and it seems the game is only going to go one way at the moment!
United need to find another gear to prevent Villa from turning this game around...
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Today, 18:06By Jack Johnson
Aston Villa 1-1 Man United
74' Rashford is off for Man United.
Fernandes has moved out wide with McTominay on to play centrally.
Villa have also made a change with Bailey replaced by Tielemans.
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Today, 18:04By Jack Johnson
Aston Villa 1-1 Man United
72' Diaby has been shown a yellow card.
He fouled Fernandes in the build-up to Garnacho's chance.
Villa are now back on the front foot.
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Today, 18:03By Jack Johnson
CHANCE! Aston Villa 1-1 Man United
71' Garnacho fires inches wide!
After all of Villa's pressure, United get a rare attack and storm forward out wide.
Garnacho cuts inside and space opens up to shoot but his effort bounces just wide of the post!
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Today, 18:02By Jack Johnson
Aston Villa 1-1 Man United
70' Watkins presses Onana to the touchline!
He concedes a goal-kick but the press gets the Villa fans up!
The atmosphere inside the stadium is superb!
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Today, 18:01By Jack Johnson
Aston Villa 1-1 Man United
68' Villa Park is rocking now!
The momentum is with the hosts and they're piling on the pressure now with just over 20 minutes to go.
Man United are going to have to grind this out now!
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