While Avram Grant is hoping that West Ham provide Chelsea with some neighbourly help at Old Trafford on Saturday, those close to Sir Alex Ferguson believe that he's jittery about the prospect of facing Alan Curbishley's team in a match that now has a crucial bearing on the outcome of the Premier League title race.

Grant, jubilant after Chelsea's 2-1 win over the defending champions knows that United's vastly superior goal difference means the result will count for nothing if United take maximum points from their final two games - at home to West Ham and away at Wigan.

"They've dropped points against West Ham in recent seasons," said the Chelsea manager. "They could do so again. And Wigan is not an easy place to go either."

Chelsea's deserved victory at the weekend has suddenly robbed United's title push of impetus and undermined the mood of confidence that has developed since they overhauled Arsenal at the top of the table in mid-March.

Although United remain clear favourites to retain the trophy, Ferguson knows that few rivals during his 21 years as United manager have proved as unpredictable as West Ham.

It still irritates him that West Ham's performance on the last day of season 1994-95 cost United the title. A 1-1 draw at Upton Park gave the trophy to Blackburn by a single point, despite their 2-1 defeat at Liverpool. Three years earlier, a solitary Kenny Brown strike virtually handed the final Football League Championship, before the advent of the Premier League, to Leeds United.

At Old Trafford, West Ham can collapse dramatically as they did in April 2000 when Harry Redknapp's team - including Rio Ferdinand and Frank Lampard - lost 7-1. But, since then, West Ham have secured three unlikely 1-0 wins there, including the victory secured by Carlos Tevez's goal on the last day of last season.

If West Ham could deny United a victory on Saturday and Chelsea were to take points at Newcastle on Monday, then the final day of the season could be as dramatic as that of 1998-99 when United beat Spurs 2-1 to reclaim the title on 79 points from Arsenal who finished a point behind.

West Ham midfielder Mark Noble warned: "We're going to Old Trafford determined to play our best.

"We have nothing to lose while they have to win. We can go out and enjoy ourselves against some of the best players in the world and savour what will be a special atmosphere."

And Grant said: "The pressure is on United because we have come from nowhere. When United went to the top they were thinking they'd won the championship but now they are under pressure and I hope that will help us."

Chelsea are now unbeaten in 81 Premier League games at home and will be confident of winning their final match against Bolton at Stamford Bridge on 11 May.

If Ferguson wanted to clinch the title at Stamford Bridge it certainly wasn't evident in the make-up of his team.

Cristiano Ronaldo and Tevez were on the bench, leaving Wayne Rooney as a lone and increasingly frustrated striker.

Chelsea were the better side early on. They passed the ball as well as at any time this season while using Didier Drogba to unsettle the United defence.

Michael Ballack was outstanding and scored both Chelsea's goals - the second a disputed penalty. Ferguson claimed referee Alan Wiley was wrong to punish Michael Carrick for handling the ball in the 86th minute - and wrong again when, earlier, he ignored Ballack's manhandling of substitute Ronaldo in the penalty area.

He said: "It was a diabolical decision. If we're not going to get these decisions then we are under pressure. The good thing, of course, is that our fate is still in our hands."

However, there is a suspicion that the tension is beginning to get to United.

Ferdinand unintentionally kicked a female Chelsea steward immediately after the match - he has since apologised - and the FA are keen to view TV footage of the brawl that developed between United players and Chelsea groundstaff on the pitch after the match.

Ultimately, the distraction of the Champions League could have a key role to play. United face Barcelona in their semi-final second leg tomorrow while Chelsea play Liverpool at Stamford Bridge on Wednesday.