Andre Agassi significant championships. In 1998, Agassi began a rigorous conditioning program and worked his way back up the rankings by playing in Challenger Series tournaments, a circuit for pro players ranked outside the world's top 50. After returning to top physical and mental shape, Agassi recorded the most successful period of his tennis career and also played classic matches in that period against Pete Sampras and Patrick Rafter. In 1998, Agassi won five titles and leapt from No. 110 to No. 6, the highest jump into the top 10 made by any player during a calendar year. At Wimbledon, he had
David Wheaton in 1991. He won the Grand Slam Cup in Munich, beating Michael Chang in straight sets in the final 7–5, 6–2, 6–4. He also reached the semi-finals of singles at Wimbledon (beating Petr Korda, Cédric Pioline, Ivan Lendl, Jan Gunnarsson and Andre Agassi in the quarter-finals before being knocked-out by Boris Becker), and was a men's doubles runner-up at the Australian Open (partnering with his former Stanford teammate Patrick McEnroe). Wheaton reached his career-high singles ranking of World No. 12 in July 1991. During his career, Wheaton won three top-level singles and three doubles titles, representing the US in Davis