Defending champion John Isner overcame two rain delays to advance in straight sets, while Andy Roddick was eliminated from the Winston-Salem Open on Wednesday. The third-seeded Isner, ranked 10th in the world, needed only 71 minutes after the two delays to beat 13th-seeded Jurgen Melzer of Austria 6-4, 6-3 in the third round at the Wake Forest Tennis Complex.