Manchester United boss Ruben Amorim defended his decision to take off captain Bruno Fernandes as the hosts suffered a 3-2 defeat to Nottingham Forest at Old Trafford.
Nikola Milenkovic, Morgan Gibbs-White and Chris Wood scored as Forest inflicted a second straight defeat on Amorim's side in the Premier League.
Fernandes was one of the better players for United on the pitch and scored their second goal in the 61st minute to set up a tense finish to the game.
But the Portugal international was substituted in the 75th minute, with Mason Mount replacing him as United failed to find inroads into the Forest defence.
"Bruno was too tired and I wanted Mount to play that position of second midfielder who opens a bit on the left," Amorim told Sky Sports after the game.
"Joshua [Zirkzee] plays with Rasmus [Hojlund] to have combinations, [Leny] Yoro goes off because we can't give him too many minutes.
"We put Harry Maguire on because of set-pieces, to control more who was winning all the first balls, the only way to attack Nottingham was transitions, to try and win first and second balls. When Harry was on the pitch, he won all the first balls."
Fernandes was also denied by the woodwork from a free-kick in the first half as United dropped to 13th in the table. They were also beaten 2-0 by Arsenal at the Emirates Stadium on Wednesday.
"It's not a surprise because we come in the middle of a lot of games," said Amorim.
"It's really disappointing for the fans, after so many times with disappointment, but we are here to do a job and will continue doing the same things to improve the team."
Meanwhile, their opponents moved to fifth place with another impressive victory and are now only two points behind champions Manchester City above them.
Nuno Espirito Santo's side have won seven matches and drawn and lost four apiece to collect 25 points from 15 matches.
Forest scored inside two minutes in both halves at Old Trafford to bounce back from a 3-0 defeat to Manchester City during the midweek.
"The belief of the players, believing every action is important [to scoring early goals]. The beginning of the second half was very good for us too. Composure was good. The team is growing, and improving. We still have things to address but it's nice," Nuno told BBC Sport.
"It's very important always to bounce back after a bad result. We didn't have a bad performance against City. Fresh leg made a difference during the game."
While United face City in their next Premier League outing, Forest welcome Aston Villa in their next outing.