Rafael Nadal defeated which 19-time Grand Slam titlist in the 2008 French Open for his fourth straight clay major title?
Roger Federer:  Federer has won 19 Grand Slam singles titles, the most in history for a male tennis player and has held the world No. 1 spot in the ATP rankings for a record total of 302 weeks, including a record 237 consecutive weeks.
i don't know