Harry Maguire said there was "no excuse" for Manchester United's FA Cup defeat to Leicester City, despite a "relentless run of games" for his side.
United were beaten 3-1 by the Foxes at the King Power Stadium to end Ole Gunnar Solskjaer's side's 29-game unbeaten away record in domestic competitions.
Brendan Rodgers' men were on top at the start and made United pay when Kelechi Iheanacho capitalised on Fred's loose backpass, rounded Dean Henderson and fired Leicester ahead.
Mason Greenwood equalised for the visitors, but Youri Tielemans scored early in the second half to put the hosts back in front. Iheanacho, formerly of Manchester City, put the Foxes two goals ahead 12 minutes from time and made sure of United's exit from the competition.
Maguire took to Instagram following the defeat and explained that United's fourth game in 10 days may have impacted the side's display on Sunday, having secured Europa League progress in Milan on Thursday.
The caption read: "A tough one to take - It's been a relentless run of games and today [it's] shown, still no excuse we know we must do better.
"Still lots to play for and we must bounce back #MUFC", accompanied by a red circle emoji.
Solskjaer made five changes from the side that won 1-0 against AC Milan, with the likes of Bruno Fernandes, Luke Shaw, Daniel James and Scott McTominay all starting from the bench in Leicester.
Despite the hectic schedule for United, they now have just under two weeks until their next game, when they host Brighton & Hove Albion on Sunday, April 4.
The Reds' only realistic chance of winning a trophy this season following the FA Cup exit is in the Europa League, where they face Granada in the quarter-final, with the first leg set to take place on April 8.
