Ole Gunnar Solskjaer has voiced his frustration over how Manchester United's preparations for their derby against Manchester City have been impeded by the scheduling of their midweek FA Cup tie.
United cruised through to the quarter-finals at second-tier Derby on Thursday, when Luke Shaw's second career goal and two strikes from January signing Odion Ighalo wrapped up a 3-0 win.
Europa League football this season means United are used to playing on Thursdays, but City have an extra day to prepare for Sunday's Old Trafford encounter after beating Sheffield Wednesday the previous evening.
"It's that help we get from the FA again - that extra 24 hours that they've had," Solskjaer said.
"I cannot believe why there's a derby on Sunday and we've got to play Thursday night. What's the point in that? That doesn't level the playing field."
City also had an extra day ahead of December's derby at the Etihad Stadium, although Marcus Rashford and Anthony Martial scored in a shock 2-1 win for United.
Solskjaer aired a similar grievance about the Premier League after winning at Chelsea last month on a Monday, saying he could not understand why they did not play on the Saturday following the winter break.
Asked if he had complained about the scheduling this time, the Norwegian said: "No, I've not. I don't think we can. It's one of those where you get told when you're going to play, so we've not got any help before this one."
United go into the derby with some momentum, having set up an FA Cup quarter-final with Norwich and taken their unbeaten run to nine matches in all competitions.
Solskjaer's side has risen to the big occasions this season, including December's Premier League win at the Etihad Stadium and a 1-0 triumph there the following month in the League Cup semi-finals.
Old Trafford defeat
But that second-leg victory was not enough to make up for the 3-1 loss inflicted by Pep Guardiola's men at Old Trafford, where a poor start proved their undoing - something Solskjaer knows cannot be repeated.
The United boss admitted his players' heads "went for a little while" in that match after City took the lead through Bernardo Silva's superb strike.
"It wasn't an issue until our heads went for a little while, so we've got to control our emotions more," said Solskjaer.
"And we have, we have learned, so that's an experience we'll bring into this game definitely."
Harry Maguire is a doubt for the derby after rolling his ankle in training and missing the match against Derby, the day of his 27th birthday.
"Well it's touch and go because he rolled his ankle and he twisted his ankle but hopefully he'll recover quickly," Solskjaer said.