Top-seeded Novak Djokovic has advanced to the quarterfinals of the US Open, where he will face fellow Serbian Janko Tipsarevic.
Third seed Roger Federer of Switzerland breezed into the final eight, losing just three games in a straight-set win over Juan Monaco of Argentina in a match that did not begin until nearly midnight. Federer will next face eighth-seeded Jo-Wilfried Tsonga of France, who beat Federer in the quarterfinals at Wimbledon.
On the women's side, top seed Caroline Wozniacki of Denmark lost the first set to Russia's Svetlana Kuznetsova, and trailed four games to one in the second set before rallying to win the match. The victory sets up a quarterfinal matchup between Wozniacki and Andrea Petkovic of Germany.
American Serena Williams also moved on to the final eight, cruising past former world number-one Ana Ivanovic of Serbia 6-3, 6-4.
The women's quarterfinals begin today with second seed Vera Zvonareva of Russia taking on Austrian Samantha Stosur, and Italy's Flavia Pennetta going against Angelique Kerber of Germany.
Men's second seed Rafael Nadal, fourth-seeded Andy Murray and the fifth seed, David Ferrer, are among the men who will try to secure their spot in the quarterfinals Tuesday.