For the home side, the big injury news is the absence of Ander Herrera who, according to Jose Mourinho, will be out for "a few weeks" after the midfielder sustained a recurrence of a muscle injury early on in midweek.
But we shouldn't forget that Sir Alex didn't have it all his own way in Europe and his record particularly against Spanish teams wasn't the best.
He claimed three Premier League titles, an FA Cup and three League Cups over two stints but was twice sacked.
Athletic Bilbao beat United comfortably home and away in the Europa League in 2012, too.
"When I play at Stamford Bridge, some rejections from fans are just reactions". "To play against Chelsea will mean less and less and less with the years", he said. I'm not so sure.
"Sometimes it looks like we have to give everything to the players and they give nothing back to us". Ander Herrera's injury meant the France global would come on after just 17 minutes, with the midfielder going on to put in a solid if unspectacular display.
Having lost this game last season, the Italian will be looking to get one over his adversary in the weekend - and what better time to inflict a defeat on the Red Devils than now - when both sides with similar ambitions converge at a crunch time of the year.
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De Gea, although, expressed his delight to make an important save during the game, he also admitted that Vincenzo Montella's side deserved more.
"I think it is the other way round, I don't think it's about the manager to trust the player, it's about the player to make the manager trust him, it is as simple as that", Mourinho said. It's how you deal with them nerves and it's how you put that on a football pitch.
Teams were anxious about what was going on in their defensive third and what we were doing.
You could often tell in the tunnel that we would have teams beat and the current approach feels like a million miles from that. It's what I would have expected.
Mourinho, 55, has been involved in a public spat with Antonio Conte in recent months but the Portuguese refused to dredge up any more abuse for the current Chelsea manager ahead of this crucial top four clash.
I think the Pogba thing is a sad story, I think Ferguson remember let him go for nothing, and I think he was right.
Lukaku has failed to score in all 17 Premier League games involving Sunday's opponents - including 10 league appearances made in a Chelsea shirt - but Mourinho is unconcerned.