Mourinho also reaffirmed his belief that United have been disadvantaged by the fixture scheduling this Christmas.
The Leicester match was the first of four top-flight games in 10 days for his side and Mourinho has already stated that he feels that the second most expensively assembled squad in world football has been “punished” by the festive fixture list.
“I’m not just saying about the privileged ones with six days to recover and to enjoy and to prepare for the next one,” Mourinho said.
“But also the ones with a little bit more time than us, for example the ones that play after tomorrow – that extra day means a lot.
“It means probably they are not working today, it means they can be back to work tomorrow and prepare for the next day. The problem that I see here is the difference between some teams.
“But what I call the December injuries in English football are arriving. Some players are leaving the pitch after 15-20 minutes, some others don’t resist for the 90.
“Of course it depends on many factors, but we open the door for what I call the December injuries.”