Roddick won 22 points at the net Tuesday and beat Gael Monfils 7-6 (2), 6-4.
The willingness to move forward is part of Roddick's more well-rounded game under Larry Stefanki, who became his coach in December. Roddick leads the ATP Tour in victories this year with a record of 26-4.
While the No. 5-seeded Roddick has improved his volley and backhand in recent months, he still possesses an overpowering serve and won 38 of 44 first-serve points against the No. 9-seeded Monfils.
Novak Djokovic also advanced to the quarterfinals when he beat No. 21 Tomas Berdych 6-3, 6-2.
