Cristiano Ronaldo proved his credentials to wear the famed Manchester United number seven shirt with a dazzling FA Cup-winning display against an outplayed Millwall side in Cardiff.

Ronaldo's predecessors read like a who's who of United greats, with David Beckham, Eric Cantona, Bryan Robson and George Best among them.

However, the teenager signed to replace Beckham last summer for the princely sum of £12.24million is proving week by week that he is more than capable of rising to the task.

Still just 19, he may occasionally still dive and may even over-elaborate with an exaggeration of step-overs.

However, in a one-sided cup final, Ronaldo not only lit up the game with his array of tricks, but provided the end product in scoring the 43rd-minute header which put United en route to victory.

With Ruud van Nistelrooy also converting a 64th-minute penalty, there was no way back for their First Division opponents and the Dutchman also struck anotheramid more than a hint of offside.

Player-boss Dennis Wise may have dreamed of recreating his part in Wimbledon's upset of 1988, but this was instead Chelsea's 1994 mauling by United all over again.

However hard Millwall ran and battled, United were simply a class apart and while the FA Cup is by no means Sir Alex Ferguson's top priority, it has at least allowed him a climax to the season.

For while the FA Cup will never replace the Premiership and Champions League, trophyless seasons are rather unthinkable at Old Trafford.

With Wise adopting an extremely low-key approach before kick-off, Ferguson had led the teams out alone in Cardiff's Millennium Stadium.

More strangely, the Millwall boss was just as inconspicuous in the opening exchanges, preferring to sit deep and try to mark Paul Scholes out of the game.

Then again, Millwall's entire policy was one of containment, with a five-man midfield and Neil Harris virtually isolated up front on his own as he gamely chased lost causes.

United initially let them off the hook as van Nistelrooy placed an early header wide and Roy Keane's volley was superbly tipped over the bar by Andy Marshall.

It was still rather a half-baked affair, with even a streaker keeping his clothes on, and Millwall were restricted to rare counter-attacks, mainly through the lively Paul Ifill.

United first looked to have made the breakthrough just before half-time, only for Darren Ward to hack the ball off the line after Ronaldo's shot had squirmed under Marshall's body.

However, it was only a couple of minutes before they did get the goal which they deserved for their patient siege of the Millwall goal.

When Keane spotted Gary Neville on the overlap, he spread the ball out wide and, having taken one touch, the England full-back crossed invitingly for Ronaldo to stoop and head past Marshall.

The Portuguese winger's finish was matched by the superb block tackle by two stewards on the spectator who charged from the Millwall end to confront the United goalscorer.

Then again, the club's player-manager was also reacting irresponsibly, with Wise pulling Scholes to the ground and then pushing away Neville as he lost his cool in the fiery moments before half-time.

If Ronaldo is tipped for stardom, then Darren Fletcher is also highly rated by Ferguson and his dazzling run just after the restart deserved a better finish.

Marshall also produced a smart save to deny Scholes, while Wise, who had finally been booked for leaving his boot in on Ryan Giggs, but did manage to clear Mikael Silvestre's header off the line.

However, the match was effectively over with 25 minutes left when former Arsenal trainee David Livermore brought down Giggs in full flight inside the penalty area.

Van Nistelrooy may have missed three of his previous five spot-kicks, including rattling the bar against Arsenal at Old Trafford, but this time he made no mistake.

With the game petering out as a contest, Giggs was able to canter through the Millwall defence to cross for van Nistelrooy - seemingly offside - to finish from close range.

Millwall substitute Curtis Weston became the youngest player to play in the FA Cup final at just 17 years 129 days, while the club are already guaranteed a place in the UEFA Cup next season.

However, United were a class apart, even if van Nistelrooy was strangely voted the official man of the match.

Ferguson nevertheless knew exactly who had proved the difference as Ronaldo was given a warm hug and round of applause from the United boss as he was substituted late on.

Not bad for a supposed one-trick show pony.

Teams:

Man Utd: Howard (Carroll 84), Gary Neville, Brown, Silvestre, O'Shea, Ronaldo (Solskjaer 84), Fletcher (Butt 84), Keane, Giggs, Scholes, van Nistelrooy.

Subs Not Used: Phil Neville, Djemba-Djemba.

Goals: Ronaldo 44, van Nistelrooy 65 pen, 81.

Millwall: Marshall, Ryan (Cogan 74), Ward, Lawrence, Elliott, Sweeney, Livermore, Wise (Weston 89), Ifill, Cahill, Harris (McCammon 75).

Subs Not Used: Gueret, Dunne.

Booked: Wise.

Att: 71,350

Ref: J Winter (Cleveland).