Roger Federer is a player of tennis.
The ATP Rankings are the Association of Tennis Professionals ' ( ATP ) merit-based method for determining the rankings in men 's tennis . This article details the list of men 's singles Grand Slam tournaments tennis champions . Roger Federer . Federer has won 18 Grand Slam singles titles , the most in history for a male tennis player , and held the No. 1 spot in the ATP rankings for a record 237 consecutive weeks and a record total of 302 weeks .