London - Jose Mourinho has played down Manchester United's chances of Champions League glory, saying English domestic fixture congestion will work against the three-time European champions.
The Premier League pacesetters are set to open their campaign against Swiss champions Basel at Old Trafford on Tuesday after qualifying for the competition by winning the Europa League.
Mourinho rested key players in Premier League matches towards the end of last season in order to save them for Europe, which he believed offered their best chance of Champions League qualification.
Real Madrid and Juventus, who contested last season's Champions League final, were also able to keep players fresh for Europe but still won their domestic leagues, while United finished sixth.
According to Mourinho, both Real and Juve enjoyed an easier domestic schedule, pointing to the lack of a winter break in England.
"The only thing I can say is that Real Madrid last year played the last month in La Liga with the second team," he said. "They could do it. And they arrived in the Champions League final with a fresh team.
"Juventus, because they were champions in Italy three months in advance, they could play... with the second team and arrive fresh for the quarter-final, the semi-final, the final of the Champions League."
The United boss said it was impossible for English teams to do likewise because usually competition in the domestic game remained fierce until the end of the season.
Mourinho said he had "no complaints" about how English football was set up and that he had the option to rest players.
"I know it goes against us but I have to admit I love the English Christmas period of football," said the United boss.
"And then there is the fact that we have to play many times two days before the big matches in Europe and then other countries protect their clubs."
Midfielder Marouane Fellaini has been struggling lately with a calf problem, and Mourinho appeared to express irritation with Belgium manager Roberto Martinez for fielding him in the recent World Cup qualifying win over Greece despite the injury.
"He had a problem in the national team and he played against Greece and after the match, he felt the problem," Mourinho said.
Asked if Fellaini had the problem before the Greece game, Mourinho said: "Yes." He added: "When the players go to the national team, they belong to the national team."
Goalkeeper David de Gea is set to be United's first-choice goalkeeper in Europe, with Mourinho confirming he will not repeat his selection policy of last season, when back-up Sergio Romero played in the Europa League.
De Gea said that it was tough for United's players to watch the Champions League last season, with the club not involved.
He said: "It was hard to watch the Champions League games on the TV last season. For a club such as Manchester United not to be in the games was hard but now we are back and motivated to bring Champions League games to Old Trafford. We need to play our best football to win the games."