Jose Mourinho's team have a clogged fixture list across the next five weeks, which could leave them playing every midweek until the end of the season.
Their Europa League progress and backlog in the Premier League means demand is high at Old Trafford.
Following Thursday's trip to Anderlecht, where Manchester United were pegged back late on in a 1-1 draw, attentions have quickly turned to Chelsea.
The league leaders arrive in Manchester having had eight days to prepare since their 3-1 triumph at Bournemouth last Saturday.
Mourinho has also had to deal with injury blows within his squad, including Juan Mata who will not return before the end of the campaign.
Ryan Giggs is hoping Manchester United players can cope with the pressure
Giggs had to contend with many similar issues under Sir Alex Ferguson during his time at the club.
Despite a Premier League title not being on the line, Champions League qualification is being chased in both competitions left.
And Giggs says this will show which players Mourinho can rely on to hold their nerve.
"There were times in my career when the games would stack up at the end of the season, when every match seemed to have so much riding on it, when the pressure was relentless, and it was then that you discovered who had the mentality to keep on going," Giggs wrote in his column for The Telegraph.
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There is no question that the run of games facing United is punishing
"It is much the same now for Manchester United, who will have arrived back from Brussels in the early hours of Thursday morning already thinking about how they recover in the two days they have to prepare for the visit of Chelsea on Sunday.
"I have been there many times before as a player, with a league title to win at home and a European campaign to take care of mid-week and while the stakes are lower for United this season in terms of trophies, the pressure is still there.
"There is no question that the run of games facing United is punishing.
"The second leg against Anderlecht comes on Thursday and then they go to Turf Moor next Sunday for another."
A win for United over Chelsea and defeat for Manchester City at Southampton will see Mourinho's team move back within a point of fourth with a game in hand.