Dmitry Tursunov of Russia upset fifth-seeded Ivan Ljubicic of Croatia 7-6 (4), 6-3 Thursday in the second round of the Open 13.
Ljubicic had 15 aces but could not force a break point against Tursunov, who earned the only break of the match in the second set. Tursunov faces No. 4 Jurgen Melzer of Austria in the quarterfinals.
Croatia's Marin Cilic also advanced after beating Philipp Petzschner of Germany 7-6 (3), 6-3.
He next plays either No. 2 Tomas Berdych of the Czech Republic or France's Edouard Roger-Vasselin.
Top-seeded Robin Soderling of Sweden was playing his second-round match later against Frenchman Nicolas Mahut.