"I don't like to play after national games in midweek. They go, they play, some come back unhappy, some frustrated, some happy, some train very hard, some don't train," said Mourinho.
"Some travel on Thursday just to train on Friday. I cannot train with the team or prepare it. The concentration is not the same and the way we are prepare is not the same.
"It happens like this four out of five international weeks. But at the same time Portsmouth are a good team who are well organised with good players and manager.
"They made it difficult for us but the weather was not a help. It was very hot and I could see in the first half it was very difficult for the players to play intense football.
"There was no pressure on the ball and people were thinking and walking slowly on the pitch.
"I had to shake them at half-time to improve in the second half. I am happy with the points and the fact we are top of the league. But I want to play better.
"Every big club in the Premier League is playing to be top of the league and we are no different.
"We want to be first on the last day of the season. To be there now, means what it means. It is good to be there."