Louis van Gaal criticised Bastian Schweinsteiger by branding the World Cup winner's second display for Manchester United "bad."
Schweinsteiger, a £14.5 million summer signing from Bayern Munich, played the second 45 minutes in United's 3-1 win over San Jose Earthquakes.
With the exception of youngster Andreas Pereira's goal, Van Gaal was unhappy with the second-half display, including Schweinsteiger's contribution.
"He was also bad," Van Gaal said in his news conference after the International Champions Cup match at the Avaya Stadium. "There was one highlight I think and that was Pereira [the goal].
"Players can play bad and certainly when you have only three days or six days training sessions in your legs and you have to play 45 minutes.
"Everybody can say that it's easy to step in but it is not easy.
"I think the first match [Friday's 1-0 win over Club America] he played very well, and now he played bad. But that is also a process and certainly when you only have one week of training."
Juan Mata and Memphis Depay, with his first strike for United, had scored first-half goals and Van Gaal was happier with their efforts before the break against the MLS side.
"The first half I was satisfied. The players want and have performed what we want," he said.
"The defensive organisation [was good] and they have created a lot of chances -- 10 and they scored two goals, so I was satisfied. It can always be better, but I was satisfied.
"In the second half, I think we played very badly, a lot of ball losses, unnecessary, and the only highlight was the goal from Pereira and I think we don't give many chances away but we give possibilities away.
"It was a threat always and that was not necessary. Our positions in midfield were not as good as in the first half."
United's next opponents in their preseason tournament will be European champions Barcelona on Saturday at San Francisco's Levi's Stadium.