Manchester United boss Erik ten Hag left Cristiano Ronaldo on the bench during the side's 6-3 defeat to Manchester City out of "respect" for the striker, he said.
Ronaldo was an unused substitute at the Etihad Stadium despite United finding themselves 4-0 down at half-time.
Ten Hag insisting afterward the 37-year-old did not deserve to be subjected to humiliation at the hands of Pep Guardiola's champions.
"I wouldn't bring him in out of respect for Cristiano, for his big career," Ten Hag said. "It's quite simple, it's a lack of belief," he added.
"The other thing was the advantage that I could bring on Anthony Martial. He needs the minutes, but I don't want to point it out like that."
Phil Foden and Erling Haaland both scored hat tricks as City ended United's run of four straight Premier League wins.
"What I like in the last period of the game is that he is involved. Guardiola said, 'I prefer to touch the ball five times and score five goals.''