Manchester United manager Ole Gunnar Solskjaer said it is "not fair" Chelsea have been afforded 48 hours more rest ahead of Sunday's FA Cup semi-final showdown.
United will meet rivals Chelsea at Wembley for a place in the decider, not before facing Crystal Palace in the Premier League on Thursday.
Chelsea will enter the FA Cup clash having not played since Tuesday and Solskjaer questioned the scheduling as United also try to qualify for the Champions League.
"There is a concern, obviously, that they will have had 48 hours' more rest and recovery than us," Solskjaer told a news conference on the eve of the Palace fixture.
"It's not fair. We spoke about a fair scheduling going into this restart and of course it isn't.
"But I have to think about Thursday [against Crystal Palace], winning that one, focusing on that one, and then pick up the pieces after that."
United will take on Palace amid an 18-game unbeaten streak across all competitions following Monday's last-gasp 2-2 draw at home to Southampton.
The Red Devils missed the chance to climb above Chelsea and Leicester City into third position – United now fifth with three games remaining.
With United's season and future plans on the line, Solskjaer is confident his team can cope with the physical demands.
"We've not really played every three days but we definitely will now," said Solskjaer. "The next two weeks will be hectic but then again we're fit, very fit – our lads have not felt as fit as this for years, I'm sure.
"It was a big thing towards the end of last season that we felt our team wasn't fit enough, we got a few injuries, this season we've not had that kind of a problem. It's not going to be a problem and a concern for us but 24 hours, 48 hours is a big difference at this time [of the season] so we've not been handed four Aces, to put it that way, for the last two weeks."
United are set to make changes against Palace after Luke Shaw picked up an ankle injury last time out, while Paul Pogba – who has starred alongside Bruno Fernandes – could be rested.
"I've been speaking more or less every day with Paul, he knows that he wouldn't be dropped," said Solskjaer. "When Paul plays like this he wouldn't be dropped from any team in the world – France or Man United – but he's been out for a long, long time, there was a question mark before the game [against Southampton], 'How do you feel?' But he felt ready for it, which was great, so now let's see how he is.
"He's been fantastic since the restart and brought a lot to the team. There were one or two question marks before the Southampton game about who was going to play but we made the decision that we did."