Chelsea moved to within one win of the Premier League title after an awful Steven Gerrard blunder set them on their way to a 2-0 victory over Liverpool at Anfield and moved them four points clear of Manchester United.
The Londoners could win their first title since 2006 later on Sunday if United lose at Sunderland while even a draw at the Stadium of Light would effectively hand it to Chelsea.
Their superior goal difference of 10 over United could mean they could afford to lose their final game at home to Wigan Athletic next Sunday.
Didier Drogba's 33rd-minute opener and a clinching second by Frank Lampard early in the second half took Chelsea to 83 points to United's 79. Sir Alex Ferguson's side complete their fixtures at home to Stoke City.
Although Chelsea will look back on the game as an unexpectedly easy victory, Liverpool started like a train and were on top for the first half-hour.
Alberto Aquilani skimmed the bar with a well-struck 25-metre shot and then over-ran a chance when sent through by the lively Maxi Rodriguez.
Chelsea had shown almost nothing in attack but were then gifted a goal, and possibly the title, by Gerrard.
The England midfielder who was on the brink of moving to Chelsea five years ago, chose this, of all days, to deliver a totally unnecessary long-distance back-pass that was easily intercepted by Drogba, who rounded Pepe Reina with ease and rolled the ball into the empty net.
The goal clearly unsettled the hosts and Lampard and Nicolas Anelka were both given a sniff of goal soon after as Liverpool's defensive concentration wavered and they were lucky not to give away a penalty in stoppage time when Lucas tangled with Salomon Kalou as the forward bore down on goal.
It mattered little as within nine minutes of the restart Chelsea did have the second as Anelka crossed low for Lampard to sweep in his remarkable 21st league goal of the season.
That knocked the remaining stuffing out of Liverpool as their extra-time exertions on Thursday against Atletico Madrid in the Europa League semi-final kicked in.
Reina saved well from Florent Malouda and Anelka as Chelsea continued to press but in the end they will be delighted to have overcome what was supposed to have been a dangerous penultimate fence while barely breaking their stride.
It was their first league win at Anfield since 2005 and leaves them firmly on course for the League and Cup Double - they face Portsmouth at Wembley on May 15 in the final.
"This was a huge game for us and we knew if we dropped points it would hand momentum to Man Utd," Lampard told Sky Sports.
"It would be nice to win it in front of our fans - we were at a bit of a low point a couple of months ago but we dug ourselves out of it and are now in with the chance of the Double."
Coach Carlo Ancelotti, set to reap silverware in his first season in charge at Chelsea, said he was delighted his side had maintained its focus.
"It was a very important step, we played very well and deserved to win," he said.
"We are very happy but we have to stay focussed. We always said this league would be decided on the last day and I think it will be so."
United, who have not lost to Sunderland for 13 years, should take this most exciting of seasons to the final day but their hopes of an unprecedented fourth successive title now appear highly unlikely.
