#4 Marat Safin
Even before turning 20, Marat Safin had lodged victories over top-players like Andre Agassi and Gustavo Kuerten. He was poised to be the net big tennis superstar from Russia after Yevgeny Kafelnikov.
Notorious for his emotional outbursts on court, Safin regularly used to smash rackets on court. The year 2000 was the turning point in Safin's career as he won his first ATP Masters Series tournament in Toronto and headed to the US Open seeded 6th.
Safin was seeded one place behind fellow Russian legend Yevgeny Kafelnikov. He had to win two back-to-back 5-set matches en-route to his march to the final. In the final, he was up against 4-time champion and crowd favorite Pete Sampras. He beat Sampras in straight sets to win the first of his two Grand Slam titles at the age of 20 years, 228 days.