With three games remaining United have 73 points to Chelsea's 70 and both teams have a goal difference of +38.
Arsenal, still with a slim title chance, have 67 points while Manchester City, with a game in hand, occupy the final Champions League qualifying slot on 62.
United's 1-0 defeat at Arsenal last week, combined with Chelsea's last-gasp 2-1 win over Tottenham Hotspur, ensures that Sunday's Old Trafford clash will be a showdown worthy of its "Super Sunday" TV billing.
Champions Chelsea scored a 2-1 win at United at a similar stage of the season last year but Sir Alex Ferguson said his side would be fresher this time.
"The problem for us last year was emotional tiredness," the United manager told Sky Sports after Wednesday's 4-1 win over Schalke 04 booked a Champions League final showdown with Barcelona at Wembley later this month.
"This time we are fresh, we are in the final at Wembley and we are going to go for it on Sunday." United have been formidable at home in the league, dropping only two points at Old Trafford all season.
"Every time they win the title they win it at Old Trafford," said Arsenal manager Arsene Wenger. "We are comparable away from home but they get the points at home."
Ferguson's vast experience at dealing with a welter of big games at the end of the season gave him the confidence to make nine changes from the team beaten by Arsenal for the game against Schalke.
United will be back to full strength against Chelsea, assuming England striker Wayne Rooney overcomes the tight hamstring that ruled him out of contention on Wednesday.
Chelsea manager Carlo Ancelotti deserves huge credit for the way he has hauled his team back into title contention after a mid-season slump.
The Londoners, in March, were down in fifth place and 15 points off the pace with a game in hand on United.
However, Chelsea's 2-1 home victory over the leaders began the process of chipping away at the deficit and now they know another win would offer a glorious chance of retaining their title and completing one of the most unlikely comebacks for many a year.
A draw would suit United, who finish the season with a game at Blackburn Rovers and a home match with relegation-haunted Blackpool.
Chelsea end the campaign with a home match against Newcastle United and an awkward last-day trip to Everton.
Arsenal are also in action on Sunday, at Stoke City who have followed up the run to their first appearance in an FA Cup Final by taking five points from their last three league games to climb to mid-table and ensure survival.
Manchester City visit Everton on Saturday where a win would secure fourth place if Tottenham lose at home to Blackpool in the evening game.
Spurs's poor recent run has seen them slip to sixth place on 55 points. Liverpool are above them on goal difference having played a game more and will bid to continue their impressi
