Seventeen-time Grand Slam champion Roger Federer has hit back at Boris Becker's claims that he and world number one Novak Djokovic do not get along.

The retired German, who works on Djokovic's coaching team, claimed in his book that the Serbian and Federer "don't particularly like each other".

In response, the Swiss tennis star has told Becker that he has 'no clue' about the pair's relationship and how he conducts himself away from the court.

"Becker really has no idea," the Daily Star quotes Federer as saying. "Actually, he would have to know me well enough to know that I'm a relaxed guy.

"I, for one, appreciate him. I do not consider him primarily as a coach of Djokovic, but I see him as Boris Becker, a man to whom I used to look up.

"I am friendly and polite to people, without having to adjust myself. Sure, sometimes I have to pull myself together when I'm tired or not in a good mood, but that's part of the job."

Federer is preparing for the quarter-finals of the Gerry Weber Open after he beat Ernests Gulbis in straight sets.