It isn't only the fact that United are still reeling from the abysmal run of defeats that cost Ole Gunnar Solskjaer his job, sparking a search for an interim manager - which has been ended by the incoming Ralf Rangnick - before the season is totally written off.
The fact is, United have such a poor record in league games at Stamford Bridge over the past two decades that Chelsea would be the favourites even if they didn't currently top the table.
Michael Carrick (right) tries to stop Didier Drogba during Man United's visit to Chelsea in 2011
The midfielder had plenty of entertaining encounters with Chelsea, if few successful ones - here he removes a piece of seat thrown on by angered home fans in October 2012
United have claimed only three wins from 20 league visits since the 2001-02 season, drawing seven and losing 10. It is a stadium where they rarely come away with three points.
So it is asking a great deal for Carrick, United's interim to the interim, to turn the historical tide after just seven days at the helm.
The positive news for United is that Carrick played a role in two of those three wins at Chelsea - one as a player and one as Ole Gunnar Solskjaer's assistant - and so may be a good omen.
He played in United's midfield alongside Tom Cleverley in United's 3-2 win there in October 2012, en route to their last Premier League title before Sir Alex Ferguson retired.
It was a hugely controversial afternoon with referee Mark Clattenburg taking most of the headlines after he sent off two Chelsea players then failed to spot that Javier Hernandez was offside as he scored United's winner.
Carrick (right) in the dugout alongside Ole Gunnar Solskjaer at Stamford Bridge in 2019
Now it's Carrick in charge of taking United to Stamford Bridge on Sunday as stand-in manager
Manchester United's record in Premier League visits to Chelsea since the 2001/02 season.
Biggest win: 3-0 in 2001-02
Biggest defeat: 4-0 in 2016-17