Switzerland's Roger Federer s fit and fighting as he looks to get his grass season off to a good start. Photo: Michel Euler/AP Photo

Stuttgart  Record winner Roger Federer has no health or fitness concerns as he starts his grass-court preparation for Wimbledon at the ATP tournament in Halle from Monday.

"I'm doing great. I'm happy with where my game is. The body, the head, everything is ready, everything is ideal," the 20-time grand slam champion said Sunday.

The 37-year-old Swiss Federer is chasing a 10th win in Halle, in the North Rhine-Westphalia region of Germany, having lost the final last year to Borna Coric.

Federer returned to the French Open for the first time since 2015 and an impressive run to the clay-court last four has boosted his confidence.

"To be in the semi-finals again, above all in Paris after all these years, definitely gives me a boost," he said. "If I can reach the semi-finals in Paris, it is also possible in Wimbledon."

Federer first meets John Millman in Halle and can take nothing for granted having lost to the Australian at the US Open last September.

"This is a fantastic first-round challenge for me on grass," he said. "Perhaps it is just what I need."

The Wimbledon championships are at the All England Club in London from July 1-15.