While seeded plays claimed seven of the eight quarterfinal slots at stake Wednesday, Youzhny knocked off sixth-seeded Mardy Fish 6-2, 7-6 (7-0).
Youzhny won 68 percent of the points on serve and saved the only two break-point chances Fish managed. Fish was for 4-for-4 in stopping Youzhny's break chances in the second set but then was shut out in the tiebreaker.
World No. 1 Novak Djokovic posted a 7-6 (7-5), 6-3 win over Sergiy Stakhovsky and will next face seventh-seeded Janko Tipsarevic. Tipsarevic got by Flavio Cipolla 6-7 (2-7), 6-1, 6-1.
Andy Murray, the No. 3 seed, took a 6-3, 6-4 decision over Marco Chiudinelli and, like Federer, didn't face a break point. Fifth-seeded Tomas Berdych earned a shot at Murray in the next round by beating Lukas Lacko 6-1, 6-2.
The other quarterfinal pits fourth-seeded Jo-Wilfried Tsonga against No. 8-seeded Juan Martin del Potro. They played in a semifinal last week in France, with del Potro winning in three sets.
Tsonga defeated Lukas Rosol 6-3, 6-4 and del Potro topped Andrey Golubev 6-4, 6-2 in second-round matches.