Chelsea 1, Tottenham Hotspur 0.

Ricardo Carvalho stepped out of the shadows to score one of the most important goals of Chelsea's season as the champions cut Manchester United's lead at the top of the Barclays Premiership to just three points.

The former Porto defender has enjoyed an immaculate season but his efforts have often gone unnoticed as Chelsea's more high profile stars have hogged all the attention.

But, more than any other player this season, Carvalho has been the rock at the heart of Chelsea's defence.

While Didier Drogba's 30 goals may have put him in contention to be honoured by his fellow professionals, Carvalho's form has been equally exceptional when you consider the number of different central defenders he's been forced to play alongside.

John Terry, Khalid Boulahrouz, Paulo Ferreira and Michael Essien are among those who have partnered the Portuguese defender during a difficult season punctuated by injuries to key players.

So it was no real surprise that coach Jose Mourinho should sing the player's praises when he stepped forward and smashed the ball home for Chelsea's 52nd-minute match winner.

It was only his third goal in the Premiership this season and his first since his header secured a 1-1 draw for Mourinho's side at Old Trafford last November.

Mourinho said: ''I think sometimes we go day after day for the big names. Big names make big headlines and players like Carvalho are sometimes are players people forget.''

But not any more. Carvalho's strike was important enough on its own to earn Chelsea victory but it became even more significant when Portsmouth defeated Sir Alex Ferguson's Manchester United side to ensure the gap at the top remained at three points.

But the modest central defender, who has endured much of the season with a niggling ankle problem, played down one of the most significant contributions of the campaign.

Carvalho said: ''It was important. We created more chances to win but we didn't score. In the end it was 1-0 and that was okay.''

The defender is quite content to sit at the back and do his job without getting the same kind of adulation afforded to player's like Drogba, Frank Lampard and captain Terry. But there is no disputing his talent.

''I'm not a player to kick, to shout a lot. I'm a player who likes to play, to have the ball, to help my other defenders. I like to be quiet, I don't mind.

''When I have more confidence to play, I do this. I have more confidence here. But here I don't have to do so much as in Porto because we have great players in midfield and attack.''

Chelsea's victory and United's subsequent defeat on the south coast set them up perfectly for their return leg against Valencia in the Champions League tomorrow night.

The tie is poised at 1-1 and Chelsea need to score but Mourinho is hoping that midfield powerhouse Essien will be back to boost their chances.

Essien has been missing with a knee injury since the FA Cup quarter-final against Spurs at Stamford Bridge but he travelled with the squad to Valencia this weekend.

Mourinho said: ''Michael has a chance to play, a little chance. He will be with us in Valencia.''

Chelsea should have beaten Spurs by a much bigger margin but failed to take numerous chances against a side that had lost in the UEFA Cup to Sevilla just 39 hours previously.

But even then Chelsea had goalkeeper Petr Cech to thank for three vital points when he pulled of super saves to deny Mido and Dimitar Berbatov.

Tottenham must now prepare for their return leg with Sevilla at White Hart Lane on Thursday and assistant boss Chris Hughton admitted they would have liked more preparation time for their clash with Chelsea.

Chelsea refused to budge as moving the game back 24 hours would have interfered with their own travel plans to Valencia. In the end, while Tottenham bemoaned the decision, it paid handsome dividends for Mourinho's side.

Hughton said: ''It certainly wasn't the ideal preparation and anybody you speak to will tell you exactly the same.

''We would have loved to have scored a late equaliser, especially after the last couple of days.

''Chelsea had one or two chances but we always felt we were in the game. I thought the lads were a credit to the club, not least those who played on Thursday night as well. The fact that we finished so strongly and kept going right until the final whistle is testament to them.''

*Stuart Pearce has warned the Manchester City board they need to splash some cash if they are to become a top-ten Premiership force next season.

"In the summer, we need to speculate a little bit more and say right, we are going to improve the squad," said Pearce.