Mourinho believes the winter break gives clubs from other countries a huge advantage over Premier League sides.
Mourinho saw his side beat Basel at Old Trafford 3-0 on Tuesday, September 12 in their Group A opener but was not impressed with his side's lack of focus.
On the 2017 Champions League opening night, Chelsea thrashed Azerbaijani newcomers Qarabag 6-0 at home, while Manchester City and Liverpool will face Feyenoord and Sevilla, respectively, on Wednesday.
Speaking after his side’s victory, Mourinho says he does not expect any of the Premier League clubs to win the Champions League.
The Manchester United boss believes that the winter break observed in Germany, Spain and Italy has given other clubs an advantage over Premier League sides.
“I think the Champions League for these teams [big European sides] that you are speaking, and for Real Madrid, Barcelona, Bayern, I think for these teams the Champions League starts in February,” Mourinho told reporters.
“Now is just the warming up and in February when us English teams, we are trying to survive after the winter period, they will be fresh and ready after these warm-ups.
“For them this is a warm-up. I think we [English teams] are in the second level. And the second level is ‘let’s qualify’.
“Let’s get the points to qualify for the knock-out phase and when we do that, if we do that, let’s enjoy playing against the big guys.”