Mourinho knows Real Madrid face major Champions League test

Real Madrid coach Jose Mourinho admits they're in a tough Champions League group.

Manchester City are up first at the Bernabeu on September 18, with the winners of the Bundesliga and Eredivisie, Borussia Dortmund and Ajax, also providing stern tests to Madrid's hopes.

Mourinho insists his players cannot afford to make any mistakes across six gruelling games if they are to stand any chance of reaching the last 16.

He told AS: "There are not only four league champions, but three of the champions from the strongest leagues in Europe - La Liga, Premier League and Bundesliga."

"It seems to me like Italian football is struggling a bit, because only Juventus could compete with the teams we have in our group. "

"French football is certainly improving, but it's not at our level yet."

"It's a very tough group.