David O'Leary believes Leeds' late show proved the perfect dress rehearsal ahead of Wednesday's titanic Champions League semi-final clash with Valencia.

Goals from Robbie Keane and Mark Viduka in the final five minutes guaranteed Leeds European football for a fourth successive season as United stretched their remarkable unbeaten Premiership run to 13 matches.

Just three months ago Leeds were languishing in 14th place, with their season on the ropes as they headed to Manchester City for what was being billed as a relegation battle.

But how times have changed at Elland Road because O'Leary's side are currently the in-form team, with the victory over Chelsea their sixth on the trot as Leeds have now taken 33 points from the last 39.

United have also conceded just one goal in the last eight hours of Premier League football, allowing them to move back into third in the table, again trading places with Ipswich.

With it comes the riches of Champions League football, for although Leeds will at least be playing in the UEFA Cup next season, the financial divide between the two competitions is considerable.

But Leeds first have a fighting chance of reaching this season's Champions League final, adding another feather to their cap with their performance against Chelsea.

At times in the past, and especially in front of a packed Elland Road, Leeds have become frustrated at their failure to break down the opposition with the game heading into the closing stages.

Against Chelsea they spurned a number of chances in the first half, most notably from Lee Bowyer, Rio Ferdinand, Harry Kewell and Olivier Dacourt.

Then in the second period, goalkeeper Carlo Cudicini produced two spectacular saves to deny Bowyer and it appeared as if the game was destined for a goalless draw.

But Leeds refused to let any building frustration get the better of them, finally gaining their rewards, first in the 85th minute when Keane needed two bites of the cherry to score his ninth goal in 19 appearances for United.

Then man-of-the-moment Viduka, linked with Real Madrid and AC Milan this week, only added to his value by scoring his 21st of the season with a thunderbolt of an 18-yard drive just three minutes later.

O'Leary felt his side had learned another valuable lesson from Manchester United as he said: "As my players get older they have to realise they can't go out on their home ground and score three goals and run over the top of people all the time.

"If it happens, then great. But it's all about keeping your discipline, shape and patience, like the great Manchester United have managed to do and look how many games they win in the last 10 minutes.

Teams

Leeds: Martyn, Mills, Ferdinand, Matteo, Harte, Bowyer (Bakke 75), Dacourt, Batty, Kewell (Keane 81), Viduka, Smith.

Subs Not Used: Kelly, Robinson, Wilcox.

Booked: Dacourt, Bakke.

Goals: Keane 86, Viduka 88.

Chelsea: Cudicini, Melchiot, Desailly, Terry, Babayaro, Wise, Dalla Bona, Morris (Poyet 64), Le Saux (Gudjohnsen 88), Hasselbaink, Zola (Gronkjaer 77).

Subs Not Used: de Goey, Jokanovic.

Booked: Morris, Babayaro, Dalla Bona, Hasselbaink, Desailly.

Att: 39,253

Ref: S Dunn (Bristol).