The US Open Series returned on Monday with the Legg Mason Tennis Classic in Washington, D.C.
And it didn't take long to see an upset. In the main draw's first match, Gilles Muller zipped by No. 3 seed Sjeng Schalken in straight sets, 6-1, 1-0, ret.
Also advancing on Monday night was No. 2 seed Lleyton Hewitt who had little problem with Kenneth Carlsen in the opening round. In the match of the day, Raemon Sluiter edged Todd Martin in a three-set classic, 7-6(5), 6-7(3), 7-6(5). American Robbie Ginepri was also a winner.
Top seed Andre Agassi's first-round match is set for Tuesday. Although Agassi can't overtake leader Andy Roddick in the US Open Series Bonus Challenge this week, he can pull within 12 points if he takes the championship.