United pushed forward and Ji-Sung Park's shot was deflected to safety three minutes later following a flowing move involving Gary Neville and Wayne Rooney.Larsson then knocked the ball back to Rooney 25 yards out in the 12th minute, only for his effort to clear the bar.
Larsson was certainly looking sharp at this stage and sent a header into the arms of goalkeeper Gabor Kiraly in the 14th minute.
He came close after Cristiano Ronaldo's effort had been cleared high into the air.
A minute later and Larsson turned quickly after being released by Rooney only for Kiraly to make the save.
Rooney should have made the breakthrough in the 21st minute but sent a weak effort into Kiraly's arms after being set up by Larsson.
Kiraly then came to Villa's rescue after 30 minutes when he did well to get a hand to Rooney's effort following some trickery from Cristiano Ronaldo.
The England striker then delayed his shot a minute later after Larsson made the opening, allowing Wilfred Bouma to make a timely challenge.
Villa were again forced on the back foot in the 37th minute and Larsson looked certain to score.
While he got a sweet enough touch on the ball, Kiraly stuck out a leg and made the clearance.
United were on a roll at this stage and Larsson peeled away from his marker in stoppage time but could not get enough power on his header.
United started the second half brightly and Brown should have at least tested Kiraly in the 47th minute.
The central defender got on the end of a cross from Rooney but headed over the top from inside the six-yard box.
Villa retaliated immediately, however, and Juan Pablo Angel found space inside the area, only to stray into an offside position.
Ronaldo then raced forward after being released by Giggs in the 52nd minute but pulled his 20-yard effort wide of the target.
Larsson marked his debut and announced his arrival at Old Trafford by making the breakthrough in the 55th minute.
He showed good composure after being picked out by Rooney in the area to rattle a shot beyond Kiraly.
It could have been worse for Villa three minutes later had a delightful free-kick from Giggs not come back off the bar.
Hughes then headed clear a goal-bound chip from Giggs and Ronaldo found the side-netting from an acute angle.
Villa almost drew level in the 67th minute but Gary Cahill headed wide following a corner from Gavin McCann.
Then two minutes later Osbourne got clear only for Kuszczak to make a crucial block.
Villa drew level in the 74th minute through substitute Milan Baros and the goal stunned United`s supporters.
The Czech Republic striker took advantage of some slack marking to score from close range.
Larsson was rightly given a rousing reception in the 78th minute when he was replaced by Solskjaer.
Rooney almost regained the lead for United in the 85th minute only to drag his effort wide.
But then up stepped Solskjaer to score the winner for United in stoppage time after a mistake by Kiraly, who allowed the Norwegian's shot to squirm under his body.
Fergie delight with Scandinavean double actSir Alex Ferguson congratulated his Manchester United team on a 'deserved'
FA Cup third-round win over Aston Villa as he vowed to continue to battle on
three fronts this season.
Ferguson was gearing up for a replay in the midlands until substitute Ole
Gunnar Solskjaer scored an injury-time winner to give the hosts a 2-1 verdict
following a debut goal for United's loan signing Henrik Larsson.
'I think we deserved to win the game, because we made a host of chances,'
said the United boss.
'But you have to feel a bit for Villa, because when they probably deserved a
goal when they really started to become a threat to us - and I'm sure Martin
O'Neill will feel gutted at losing a goal so late in the game.'
Solskjaer's late intervention not only settled the issue but convinced
Ferguson his team have the mettle to continue to dig deep in the Cup, the
Barclays Premiership and the Champions League too.
'It is always a good indication of a side when they score late goals, because
it shows they have a bit about them,' he reasoned.
Asked how optimistic he is that his team can keep going in all competitions,
he said: 'We have to go for it. There's no point being
negative; you have to be positive and see where it takes you.'
As for his two goalscorers, Ferguson was delighted with their all-round
efforts - particularly the first impression made by Larsson.
'We had to find out about him. Playing at home in this game was a great
chance to do that, and I am pleased with him,' he said.
'He's been looking terrific in training and he could have scored three or
four goals.'
Evergreen Solskjaer, who came on in the second half for Larsson, once again
came up trumps for United when his shot squirmed under the body of Villa
goalkeeper Gabor Kiraly.
'When Ole gets in these positions you always expect him to hit the target,'
said Ferguson.
'To have nine goals so far is a phenomenal effort - I don't think anybody
expected him to score so many by this time of the year.'
Villa boss O`Neill reported Kiraly was 'distraught' after allowing the winner
from Solskjaer to squirm under his body.
'He came to us with the best of intentions, and we are grateful for him to
come when we had a goalkeeping crisis some weeks ago. Palace gave us permission
to take him on - and I am grateful to him,' he said.
'He is distraught, because it is a goal he probably should have stopped.'
O`Neill claimed Villa had their best spell when they went behind.
'Ironically we had a bit of belief about ourselves then. There was no point
letting the inevitable happen, where we lost by two and three,' he said.
'We pressed forward, and when we got equaliser it was a good spell. I thought
we deserved it.'
Asked about Larsson`s goal, O`Neill said: ' People used to say he could score
in Scotland - but could he score elsewhere? I said `no problem', providing he
gets enough service. He is as fit as he could possibly be and he will get
goals.
'For us, we are in the results business and we have to win some games.'
Manchester United 2 - 1 Aston Villa
