Manchester United moved to within touching distance of the Premiership title after Cristiano Ronaldo's penalty clinched a 1-0 win at Manchester City on Saturday.
United are now eight points clear of second-placed Chelsea and they will be crowned champions for the first time since 2003 if Jose Mourinho's men fail to beat Arsenal.
Even if the Blues win at Arsenal, Alex Ferguson's side can seal the league title on Wednesday if they avoid defeat against Chelsea.
Ronaldo's spot-kick and a late penalty save from Edwin van der Sar gave United the win over their local rivals at Eastlands.
The league leaders went in front in the 34th minute with a goal that was especially sweet for Ronaldo.
Michael Ball had been guilty of a vicious stamp on Ronaldo early in the first half, but the Portugal winger was quick to exact revenge as he drew the left-back into a rash lunge that earned a penalty.
Ronaldo picked himself up to send Andreas Isaksson the wrong way from the spot for his 23rd goal of a superb season.
City hadn't scored a home league goal since New Year's Day, but they had a glorious chance to end that barren run in the 81st minute when Ball won a soft penalty after colliding with Wes Brown.
Darius Vassell took the spot-kick, but his shot struck van der Sar's legs and deflected to safety as United held on for a potentially decisive victory in the title race.
At the other end of the table, West Ham moved out of the relegation zone thanks to a match-winning display from Carlos Tevez, who has been at the center of a bitter row over his eligibility to play for the Hammers.
West Ham's relegation rivals are considering legal action against the Premier League after the London club were only fined rather than handed a points penalty for playing Tevez even though he was not registered properly.
So it was inevitable that Tevez would play a major role in his side's 3-1 win over Bolton at Upton Park. The Argentina striker opened the scoring with a 10th minute free-kick and added a second in the 21st minute.
Mark Noble got the third and Gary Speed's second half strike couldn't stop Alan Curbishley's side edging closer to a great escape with their sixth win in eight matches.
"It's given us a great opportunity and we've got to grab it. We've come this far and not to grab it would be devastating," said Curbishley, whose team face Manchester United next week.
"We couldn't wish to go to a tougher place but we are full of confidence," he added.
West Ham's victory plunged Wigan into the bottom three after Paul Jewell's side lost 1-0 against Middlesbrough.
Wigan chairman Dave Whelan has led the protests against West Ham and it is his side who are in danger of slipping into the Championship instead after Australia striker Mark Viduka's 29th minute goal at the JJB Stadium.
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