Just two months after he was widely reported to be on his way out of Chelsea, coach Carlo Ancelotti has the chance to complete a remarkable comeback in the Premier League title race on Sunday.
Chelsea was 15 points behind Manchester United at the start of March following a dismal run of results but could now move top of the standings on goal difference with victory at the longtime leader's Old Trafford home.
That would make Chelsea a strong favorite for a second straight title and likely end uncertainty over Ancelotti's future.
The importance of the game is underlined by the fact that Manchester United's Alex Ferguson is set to recall his top players for a match he had hoped until recently would be meaningless.
Wayne Rooney, Rio Ferdinand and Nemanja Vidic are all in the squad after sitting out Wednesday's 4-1 Champions League win over Schalke, which secured a 6-1 aggregate win and place in the May 28 final.
After dropping points with a draw at Newcastle and last weekend's tepid 1-0 defeat at Arsenal, United's hopes are pinned on continuing what is by far the Premier League's best home record.
United has won 16 and drawn one of 17 games at Old Trafford, and has also beaten Chelsea there in the Champions League quarterfinals.
"Our home record is probably the best in Europe," Ferguson said. "It is the reason we are there. Some of the performances at home this season have been absolutely terrific.
"If we win, we should win the league."
Victory over Chelsea would leave United needing only a point from its last two matches against Blackburn and Blackpool to guarantee a record 19th English championship, while even a draw would put it in control.
But Chelsea's return to contention was sparked by a 2-1 comeback win over United on March 1 and a repeat result would put the Blues top by the finest of margins.
"They will fancy themselves strongly," said Fulham manager Mark Hughes, who played for Chelsea and Manchester United. "They've come very much back to the fore. Maybe two or three weeks ago, everybody thought it was done and dusted.
"But credit to Chelsea, they've kept going and got right back into the mix. It's a tough one to call."
Chelsea won the corresponding fixture 2-1 at United last April on its way to the title, ending United's three-year run of Premier League championships. That was the last time United lost at home.
A draw or win for Chelsea could also leave the door ajar, albeit only slightly, for Arsenal to make a late charge at the title - although the leading pair would both need to collapse for the third-place Gunners to win a first title since 2004.
Arsenal is at Stoke on Sunday, a team it has beaten four straight times in the Premier League.
Central defender Thomas Vermaelen could return after nine months out with an Achilles' injury, replacing Johan Djourou.
Aaron Ramsey, who scored the winning goal against United last week, could again fill in for injured captain Cesc Fabregas.
Arsenal manager Arsene Wenger said Ramsey was unconcerned at returning to the stadium at which he broke his leg in February 2010.
Stoke's Ryan Shawcross was sent off for a dangerous tackle on Ramsey and left the field in tears after injuring his opponent so badly. Ramsey has only just begun playing regularly again for Arsenal after recovering.
"When you play football you try to control the ball well and make a good pass. When you do not have the ball you try to win it back. And you do not look who is against you," Wenger said. "The foul happened a year ago. We cannot want to have a clean game and prepare for football games like that."
Wolverhampton Wanderers host local rival West Bromwich Albion in Sunday's other match.
Manchester City could effectively clinch a place in the Champions League on Saturday if it wins at Everton and Tottenham fails to beat visiting Blackpool. Blackpool already beat Spurs this season.
Also Saturday, it's Aston Villa vs. Wigan, Bolton vs. Sunderland, Newcastle vs. Birmingham and last-place West Ham vs. Blackburn. West Ham is already three points from safety and will almost certainly be relegated at the end of the season if it loses.
Fulham hosts Liverpool on Monday.