Ole Gunnar Solskjaer defended his decision to field a weakened team as Manchester United crashed out of the FA Cup with a 3-1 quarter-final defeat at Leicester on Sunday.
Solskjaer made five changes from the United side that beat AC Milan in the Europa League last-16 second leg on Thursday.
Paul Pogba was back in the starting line-up but Bruno Fernandes was left on the bench until the second half, while Marcus Rashford was missing from the squad.
United responded to the switches with a lethargic display as they were beaten for the first time in 30 domestic away games.
Mason Greenwood cancelled out Kelechi Iheanacho's opener, but second-half goals from Youri Tielemans and Iheanacho killed off United.
It leaves Solskjaer with only the Europa League left as a realistic opportunity to win the first silverware of his reign as United boss.
Insisting he had no regrets about his selection, Solskjaer said: "I would have started the same team again. Every team selection has reasons behind it.
"On Thursday Bruno broke all his records physically and the boy is not inhuman.
"He has played a game every three or four days. It was a chance to start both Donny (Van de Beek) and Paul (Pogba) but the accumulation of games maybe caught up with us.
"We knew we had substitutes who could come on and make a difference. Everyone could see we weren't as sharp as we have been."
Without a major trophy since 2017, United are 14 points behind Premier League leaders Manchester City and face Spanish side Granada in the Europa League quarter-finals in April.
"You are always disappointed, especially when it's the end of the line of a cup run. We couldn't find the normal spark, brightness and energy," Solskjaer said.
"Maybe all the games caught up with us. Thursday was a big night and today we didn't have the zip."
Brendan Rodgers urged Leicester to create history after his team reached the FA Cup semi-finals for the first time since 1982.
Leicester have made four final appearances but have never won the competition.
"We are in the semi-final and we have a chance to get to the final and create history," said Rodgers, whose side will face Southampton in the last four at Wembley in April.
"When it comes we will fight and give everything we can to achieve that.
"For the club to get to the final and win the trophy would be really special. It's a trophy in their history they haven't won. I would be so happy for the owners.
"There are lots of teams ahead of us in terms of budget or whatever else, maybe history, but the ambition is there to win titles and be competitive."