But their hopes suffered an early blow when Ronaldo picked up a loose ball from Ulises de la Cruz's wayward header and strode forward unopposed for 10 yards before unleashing a magnificent shot with the outside of his right foot that bent past Thomas Sorensen's despairing dive.
It needed a superb last-ditch tackle from Jlloyd Samuel to deny Ronaldo a second after he had tricked his way past Liam Ridgewell, then Sorensen dived low to save another Ronaldo effort as the teenager threatened to run riot.
The goal had rocked the home side and a second was not long in coming as Paul Scholes' long ball evaded Ridgeway and fell perfectly for van Nistelrooy, who calmly took it round Sorensen before stroking home his 28th goal of the season.
Villa thought they had won a penalty five minutes into the restart when Juan Pablo Angel was tripped by Wes Brown in the area but instead the Colombian was booked for diving, before United went down the other end and Ryan Giggs fired over from five yards.
Villa continued to push forward and pulled out all the stops in a bid to pull a goal back.
United were reduced to 10 men when Darren Fletcher was shown a second yellow card, before the visitors were reduced to nine after Ronaldo was also harshly sent off for his second bookable offence.
Villa had the ball in the net in the closing stages but it was disallowed for a foul on Tim Howard to add to Villa's frustrations.
With Newcastle claiming a 1-1 draw away to Liverpool, Villa knew they were without Uefa Cup football for next season, though they can take heart from some tremendous displays under David O'Leary's guidance.
Ruud van Nistelrooy has once again made it clear he has no intention of quitting Manchester United.
The Dutchman scored his first Premiership goal in three months to earn the Red Devils a 1-1 draw at home to Chelsea on Saturday, but the result meant United will have to participate in August's Champions League qualifiers after the Blues secured second spot.
The 27-year-old, who netted his 27th goal of the season following a five-game barren spell, has been constantly linked with a big money move to Real Madrid in the summer, but he insists he is "going nowhere" and will be striving to regain the league title from Arsenal next term.
Van Nistelrooy declared: "At the same time next season I will be here talking about another Premiership season because I am going nowhere."
"This result means we have finished third, which is not what we hoped for but we are confident we can improve next season."
The former PSV Eindhoven forward squandered a golden chance to level the scores just before the break when Carlo Cudicini saved his 41st-minute penalty kick- his third failure from the spot at Old Trafford this season.
But the Holland international was determined to break his duck after wasting the spot-kick and eventually found the back of the net in the 77th minute following a blunder by Cudicini for his 107th goal in his Old Trafford career.
"After the penalty, there was only one thing on my mind. I wanted a goal," he revealed.
"The run wasn't bothering me because I have missed a few games through injury and I did score against Manchester City and Fulham in the FA Cup but it was great to get one in the end."
HE is famously shy of publicity - yet Manchester United striker Ruud van Nistelrooy's wedding could be broadcast to millions around the world on the internet.
The pastor of the Maria Magdalena church in Geffen, the village in the south of Holland where Ruud and long-time girlfriend Leontien Slaats are to marry on July 10, has already ruled out TV cameras.
But he has agreed to discuss with the couple whether a web-camera could be installed inside the church.
Ruud has already said he will employ a security team to keep the paparazzi out and protect his invited guests.
But now it appears that what was going to be a very private service for invited family and friends only could have an audience of millions.
The web-cam scheme is the idea of Maurice Bosch, 20, and Thijs van Schaijk, 25, both from the same Geffen village where van Nistelrooy grew up.
They own two websites dedicated to the player.
They already plan to put two cameras on property owned by their families around the church - but they have now asked for permission to instal a camera inside the church.
Maurice said: "The pastor is going to ask Ruud if we can put one up inside the church, but he has warned us that the site must not be a money-making business.
"This was never our plan anyway. We've had requests from advertisers, but we don't want to make any money. For us, it is all about the kick of getting a million or more people visiting our site.
"The only way we can profit is if potential clients say `Did you design that website?'."
Thijs said they did not intend to pry into the couple's private life and added: "We're already getting asked questions about that but we won't do that. This is about Ruud."
He added: "We've still got to find out where we stand. In any event, the site is capable of taking an enormous number of hits, as many as his Idols website.
"The saddest thing that can happen is if the site went down just at the wrong moment."
The service at the Heiliger Maria Magdalena Church, in Geffen, will follow the completion of Dutch marriage formalities at the nearby village of Heesch, where the United ace has snapped up a £555,000 farmhouse built in 1948.
Manchester United boss Sir Alex Ferguson has once again denied that Ruud van Nistelrooy is leaving Old Trafford and moving to Spain.
Both Real Madrid and Barcelona have been linked with the Dutchman recently but Ferguson is adamant that his star striker is going nowhere.
"There has been a crescendo of speculation in the last two weeks, but it's time to put this to bed now," he said.
"There is no foundation to the gossip and I think it is important that it comes straight from everyone involved.
"As far as Ruud is concerned, we wanted to clarify whether he is going to Barcelona, Real Madrid or whether he is staying here. We are clear in our mind about that."
Van Nistelrooy added: "I'm going nowhere."
"I signed a new contract in January and I said in the past I am going nowhere.
"I want to stay and be part of the club over the next four years and I will keep reminding everybody that is the case.
"This is a good day to come out and show the fans what the real situation is. That is it."
The 27-year-old moved to Old Trafford in the summer of 2001 from PSV Eindhoven and has scored 66 goals in 96 league outings for the Red Devils.
Ruud van Nistelrooy believes Steven Gerrard will be the man to stop if Manchester United are to record a back-to-back Premiership double over Liverpool.
Although their defence of the title is almost certain to come to an end this weekend, the Red Devils are still aiming for second spot and their fans are demanding they inflict another damaging wound into Liverpool's hopes of finishing fourth.
United's hopes have already been given a lift with the news that Mike Riley - who sent off Sami Hyypia and awarded the hosts two penalties in the corresponding fixture last season - will take charge of the game after original referee Graham Poll pulled out with a hamstring strain.
Poll's appearance at Old Trafford would have been controversial anyway given his recent diving allegations against Gary Neville and Sir Alex Ferguson will no doubt be privately happy that the Tring official will not referee the game after his performance in the recent league encounter with Arsenal at Highbury drew criticism from the United boss.
However, van Nistelrooy - who converted both spot-kicks in last season's 4-0 victory - is focusing exclusively on the action on the pitch and while he accepts Liverpool would expect to be far closer to the top three than they actually are, in Gerrard the Dutchman believes they have a world class talent.
'Steven Gerrard is Liverpool's most important player,' he told MUTV.
'He is the driving force behind their team - the man who makes them play.
'He can score goals, he can run with the ball and his ability to make tackles and fight is very important to them.
'His battles in midfield with Roy Keane are always great to see.'
Van Nistelrooy, without a Premiership goal since February 11, thinks Liverpool's need to land the fourth Champions League spot makes the game more important for Gerard Houllier's men than it is for United, whose chances of finishing runners-up will rest on their ability to beat Chelsea in their final home game of the season on May 8.
But the £18.5million former PSV striker accepts the intense rivalry between English football's fiercest rivals will not allow the hosts to adopt anything less than a full-on approach to the contest.
'We know exactly what kind of game it is going to be like,' he said.
'Maybe there is more pressure on them to win because getting into the Champions League is massive these days.
'But we want the victory just as badly as they do because there is so much rivalry and competition between the two clubs.'