Federer defeated Canadian Milos Raonic, 6-4, 7-6 (4), 6-2, to secure a quarterfinal berth, while Murray downed France's Gilles Simon, 6-3, 6-1, 6-3.
Federer's next opponent is No. 7 Jo-Wilfried Tsonga, a finalist here in 2008.
Murray advances to a meeting with unseeded Frenchman Jeremy Chardy, who beat him the last time the pair met in Cincinnati last year.
Third-seeded Serena Williams, chasing her third consecutive Grand Slam title, is still on course for a potential meeting with top-ranked defending women's champion Victoria Azarenka, of Belarus, in the semifinals, with French Open champion Maria Sharapova, of Russia, the top player in the other half of the draw, likely to be the opponent for the final.
Williams and Azarenka lost just four games between them against Russian rivals. Williams beat Maria Kirilenko, 6-2, 6-0, and Azarenka defeated Elena Vesnina, 6-1, 6-1.
In the quarters, Williams will meet fellow U.S. player Sloane Stephens while Azarena meets Russia's Svetlana Kuznetsova.
On Tuesday, sixth-seeded Li Na, of China, advanced to the semifinals with a 7-5, 6-3 win over fourth-seeded Agnieszka Radwanska, of Poland.