In a second-round match, Roddick beat fellow American Scott Oudsema, 6-7 (3-7), 6-3, 6-2.
The winner served 21 aces in the match and came back after losing the first set in a tie-breaker.
Elsewhere, fourth-seeded American Robby Ginepri topped Denmark's Kenneth Carlsen, 7-6 (7-5), 3-6, 6-4; No. 7 seed Dominik Hrbaty of Slovakia beat Germany's Lars Burgsmuller, 7-5, 6-4; and No. 8 Dmitry Tursunov of Russia downed Sam Querrey of the United States, 7-5, 6-4.
In the quarterfinals, Roddick faces Tursunov; Ginepri will play Hrbaty; fifth-seeded Andre Agassi takes on No. 3 Fernando Gonzalez of Chile; and American Paul Goldstein, who knocked off Marat Safin in the second round on Wednesday, plays sixth-seeded Tommy Haas from Germany.