Roger Federer and Andy Roddick both won two matches to advance to the last eight at the Toronto Masters.
Federer defeated Robin Soderling 7-5 6-1 and then got the better of Max Mirnyi 7-6 7-6.
Roddick saw off Feliciano Lopez 6-3 7-6 before beating Argentina's Juan Igancio Chela 6-1 6-4.
But fourth seed Carlos Moya of Spain and Australian ninth seed Lleyton Hewitt were knocked out by Nicolas Kiefer and Fabrice Santoro.
Moya lost 6-4 2-6 6-4 to the German while Hewitt was also beaten in straight sets 2-6 6-3 6-4.
Federer's victory over Mirnyi extended his unbeaten streak to 20 matches, going back to the third round of the French Open.
"If someone had told me after the French I wouldn't lose
a match until now I would've told them this was almost
impossible," Federer said.