Manchester United saw off Charlton to seal second place in the Premiership and avoid the qualification rounds of next season's Champions League.
United's players celebrate Louis Saha's opening goal against Charlton
Louis Saha opened the account by heading home Ryan Giggs' corner before Cristiano Ronaldo tapped home from close range to give United a 2-0 lead.
An own goal from Jason Euell meant Alan Curbishley's last match as Charlton boss would turn into a rout.
Kieran Richardson added United's fourth with a superb long-range strike.
United needed a victory to deny arch-rivals Liverpool the runners-up spot and they set about their task with real purpose.
However, the match had been clouded with controversy even before kick-off with the news that Dutch striker Ruud van Nistelrooy had driven away from Old Trafford three hours before kick-off.
He was replaced by youngster Giuseppe Rossi, who made the most of his chance with a lively performance alongside Saha.
Charlton have only won once at Old Trafford in the last 68 years and it never looked like they would improve on that record from the opening minutes.
Curbishley - who has never won at United as a player or a manager - could see the writing was again on the wall as soon as Rossi's strike forced a good save from Stephan Andersen in the 13th minute.
Paul Scholes holds off Charlton defender Chris Powell
The Charlton keeper was then forced to block a flurry of efforts before the deadlock was finally broken when Saha directed home Gigg's inswinging corner.
Giggs was again involved when the visitors failed to clear his cross four minutes later and Ronaldo turned on a sixpence to slot home in the 23rd minute.
Jason Euell, the one change Curbishley made to his team before kick-off, panicked at Saha's right-wing cross and hit it passed the hapless Andersen 12 minutes later.
It could have been more than 3-0 at the break, with man-of-the-match Kieran Richardson's 30-yard strike coming off the underside of the crossbar and bouncing safely on the goal-line.
The arrival of Paul Scholes as a second-half substitute for John O'Shea added to the party atmosphere for United.
The former England midfielder was believed to have been ruled out for the remainder of the campaign after being diagnosed with an eye problem in December.
Scholes' incisive passing was a feature of the second period - it's a kind of magic that the Reds have missed at key games this season.
His sweet through-ball for Richardson should have brought a fourth goal but Andersen blocked well down to his left.
However, Richardson gave England boss Sven-Goran Eriksson a timely nudge for his World Cup squad when he broke forward from halfway before unleashing a superb strike for the fourth goal.
A surreal last 10 minutes surrounded Old Trafford as the certainty of second place was confirmed and United strolled to their 13th home win of the season.
Charlton boss Alan Curbishley: "It was a disappointing way for me to end as manager.
"The chairman made the decision for me to go because they need to sort things out quickly.
"They thought there would be problems when I didn't sign a new contract and the decision was made to do it now so they have time to get a man in and see what players he'll need.
"It was always going to happen at some stage but it's better to be clapped out of the front door than kicked out of the back door."
Manchester Utd: Van der Sar, Neville (Vidic 62), Ferdinand, Brown, Silvestre, Ronaldo, O'Shea (Scholes 45), Giggs, Richardson, Saha (Solskjaer 61), Rossi.
Subs Not Used: Howard, Fletcher. Booked: Richardson.
Goals: Saha 19, Ronaldo 23, Euell 35 og, Richardson 58.
Charlton: Andersen, Sankofa (Fortune 45), Sorondo, Perry, Powell, Holland, Kishishev, Euell (Ambrose 61), Hughes, Bartlett, Darren Bent (Sam 45).
Ref: M Atkinson