Bayern Munich chairman Karl-Heinz Rummenigge insists there'll be no problem with Renato Sanches' age.

Rummenigge is proud of their deal for Benfica midfielder Sanches, who was also wanted by Manchester United.

However, doubts continue to be raised over the 18 year-old's age.

"We will check everything. Renato Sanches has hospital documents complete with a birth certificate, photos and video. He has taken a big leap in development from 16 years of age and must have worked a lot in the gym.

"Sanches is 18 years old, of this we have no doubt."