Roddick defeated Lee, 7-6 (8-6), 6-2, in what was their second quarterfinal meeting in as many weeks.
Isner, ranked 416th in the world and appearing in only his second ATP tournament, defeated Haas, 6-4, 6-7 (6-8), 7-6 (7-5). Haas had been seeking his 400th career victory on the ATP Tour.
Monfils was a 6-3, 7-5 winner over Safin and will take on Isner in the semifinals.
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