MADRID: Jose Mourinho says Real Madrid cannot afford the slightest error in their difficult Champions League group, and he predicts a tough battle with Manchester City.

“The difference between our group and the rest is that Madrid cannot make the slightest error,” Mourinho said in an interview with sports daily AS published Thursday.

In the group phase, La Liga champions Real Madrid face Premier League champions Manchester City, Bundesliga champions Borussia Dortmund and Dutch league champions Ajax Amsterdam.

“It's not just that there are four champion clubs. Of the four champion clubs, three won in the three biggest leagues in Europe: La Liga, the Bundesliga and the Premier League,” he said.

Manchester City would be a serious challenge, Mourinho warned.

“City are a team made to win the Champions League, built with that goal in mind. The investment they have made year after year is precisely with the aim of conquering the Champions League.”

The Real Madrid-Manchester City clash would be tough, he said.

“It will be very hard. Hard for Real Madrid and hard for them, because Madrid is Madrid.”

But the self-proclaimed “Special One” said Dortmund, too were a serious rival.

“They are double champions of Germany, an excellent team full of internationals but who also have the two best players of Poland,” he said.

“And Ajax, you never know, they can give you a surprise.”