Capello was able to cast his eye over a combined tally of nine players in the two starting line-ups who were eligible for England selection.But it was Portuguese star Ronaldo who broke the deadlock with nine minutes remaining, before substitute Rooney wrapped up the game in the dying seconds. It means United have now won 13 successive matches against Villa.
Sir Alex Ferguson's side just about deserved their victory, with Ryan Giggs and Rooney both squandering gilt-edged chances to settle the tie before Ronaldo struck.
• Rooney is Fergie's new supersub
Villa would have been disappointed with their lack of a cutting edge and United goalkeeper Edwin van der Sar did not make a meaningful save in the entire 90 minutes.
Ferguson maintained his proud record of never having lost a third-round tie in the competition.
There had been much pre-match hype about Villa striker Gabriel Agbonlahor being a contender for Capello's first England squad, but he failed to sparkle.
Capello took his place at the front of the directors' box, where he was flanked by Football Association chief executive Brian Barwick and director of communications Adrian Bevington.
Agbonlahor gave an early demonstration of his pace to the Italian with a break down the left flank before squaring an inviting low cross towards Stiliyan Petrov, but his first touch was a poor one and Van der Sar was able to collect.
Anderson was quick to spot a gap down the middle and made a powerful 50-yard run, which ended with Scott Carson saving his left-footed drive from the edge of the Villa box at the second attempt.
Petrov was only just too high with a dipping 30-yard drive in an open-ended start to the game. Agbonlahor turned sharply, but Rio Ferdinand was alert to the situation and blocked his shot.
United started to enjoy more of the play territorially, with Anderson looking threatening in the centre of the park.
The Brazilian made another good break into the Villa box, only to be eventually crowded out by the combined efforts of Nigel Reo-Coker and Wilfred Bouma.
John Carew had a rare sight of the goal after turning Ferdinand when running onto a Petrov pass, but he could not convert.
Giggs missed a golden chance to put United ahead a minute before the interval after a mistake by Carson.
The on-loan Liverpool keeper should have dealt better with a dipping drive from Ronaldo, but only parried it straight to Giggs.
However, with the goal at his mercy, the former Wales international pushed his shot wide and seemed surprised by the pace of the ball.
Villa began the second half brightly and Carew flicked on a Young centre, which Van der Sar saved down to his right, even though the ball was going wide.
Michael Carrick teed up Anderson on the edge of the Villa area and although his shot contained plenty of power, it flew well wide of Carson's goal.
Petrov blocked a shot from Ronaldo and then Martin Laursen was relieved when he deflected a Nemanja Vidic header past his own post from a Giggs corner.
Rooney could have won the game for United after entering the action, but he shot over the bar after exchanging passes with Ronaldo.
However, with nine minutes left, Ronaldo scrambled the ball over the line from a Giggs centre for his 19th goal of the campaign.
Then, with 60 seconds remaining, Rooney drilled a powerful shot past Carson into the corner of the net after Ronaldo's initial effort had been blocked.
Rooney is Fergie's new supersubWayne Rooney's introduction changed the game and led Alex Ferguson to joke afterwards: 'I have been trying to find a new Ole Gunnar Solskjaer as a substitute -
although I don't think Wayne would appreciate that,' laughed Ferguson.
'Wayne changed the game when he came on. He brought us thrust and enthusiasm
and direct play. He attacked defenders and made a heck of a difference to the
game.'
'It is difficult to say why we have such a good record here,' said
Ferguson.
'It is a traditional, old-fashioned football ground. The fans are right on
top of you and there is always a good atmosphere.'
After clarifying his feelings about the lack of atmosphere at Old Trafford
during the New Year's Day win over Birmingham yesterday, Ferguson also
reinforced his belief United's travelling fans are among the best.
'We had 7,500 fans here, who had a real party,' he said.
'Every time we come to Aston Villa, they are really up for it. They can make
a difference, which is the point I made last week.
'When our fans are like that, we do not let them down.'
With at least eight Premier League sides on the way out of the competition
after a day of FA Cup shocks, United are already well placed to at least emulate
their appearance in last season's final.
And Ferguson knows exactly who he would like to be pitted against in Monday's
fourth round draw, a Peterborough side managed by son Darren.
'You hope for a home draw, but I would like Peterborough, just to give
Darren's club some money.'
Ferdinand said about Rooney on BBC1: 'I think he's a fantastic footballer.
'He's been out for a couple of games. He looked very, very fresh when he came
on.
'He's a player who's got bundles of energy.'
Ferdinand also applauded the perseverance of Ronaldo, saying: 'It was a
scruffy goal but he scores goals.
'No matter how they go in, it's great for us.'
Ferdinand insisted there was no thought of settling for a draw with the clock
ticking down.
He said: 'It's not in our nature. The manager wouldn't settle for that
either.'
And the defender insists the competition is high on his list of priorities.
'It's up there with the top things to win,' he said.
'We don't go into any competition thinking we don't care about the
tournament. I think that's disrespectful for the tournament.
'If we could win that cup, it would be fantastic.'
Villa manager Martin O'Neill claimed it 'never entered his head' whether young
England candidates Gabriel Agbonlahor and Ashley Young were affected by the
presence of Capello.
Agbonlahor and Young have been in outstanding form during the first half of
the campaign but made little impression against United after a bright opening 15
minutes.
O'Neill said: 'Were they affected by Capello's presence? It never entered my
head. Was he here today? But then I'm not 21 and wanting to play for England.
'I am sure Fabio will have plenty of time to assess all the English players
between now and the summer before the main business starts for him in September
with the World Cup qualifiers.'
He added: 'The game looked as if it was heading for a replay.
'I didn't think we deserved to lose but also didn't do enough to win it. I am
disappointed because with 10 minutes to go I thought a replay was on the cards.
'We put in a big effort and they did not put us under sustained pressure
although we didn't do the same either to Manchester United.
'We are disappointed because we are better than today's performance. We had
plenty of determination but didn't do enough although I still feel we deserved a
draw.'
Aston Villa 0 - 2 Manchester United
