Steffi Graf

Graf's first year as a professional was tough. She did not win any tournaments, though she did make it to the semifinals of the U.S. Open, losing to Martina Navratilova. But then in 1986 she won 24 straight matches, quickly moving up to the number three ranking in the world.

But Graf was not satisfied. She wanted a Grand Slam, and therefore began a rigorous training program that included running, weightlifting, jumping rope, and more and more tennis. She made her hard work pay off, and in 1987 won the French open against Navratilova (6-4, 4-6, 8-6). At that time, in French Open history, she was the youngest winner ever, and with her victory moved her ranking up to number two in the world.

Soon she moved up to number one, following her many other victories that year. By the season's end, Graf had lost only two of seventy-two matches, winning an amazing 11 of the 13 tournaments she played in.