STOCKHOLM (AP)—Top seed and former champion Tomas Berdych beat Dustin Brown of Germany 7-5, 6-3 to reach the quarterfinals of the Stockholm Open on Thursday.

The Czech, who had a bye into the second round, is coming off the Beijing final and Shanghai quarterfinals. He needs to reach the final here to stay in the running for a berth in the eight-man ATP Finals.

Next up for Berdych, the 2012 Stockholm champ, will be Marius Copil of Romania, who beat fellow qualifier Pierre-Hugues Herbert of France 6-4, 6-3.

Jack Sock of the U.S. put away sixth-seeded Jeremy Chardy of France 7-6 (3), 6-3 to line up defending champion Grigor Dimitrov in the quarterfinals, and qualifier Matthias Bachinger of Germany hit 15 aces as he upset fifth-seeded Leonardo Mayer of Argentina 7-6 (3), 6-7 (4), 6-3.

Fourth-seeded Alexandr Dolgopolov of Ukraine fell to a third straight loss in his comeback from a knee operation, in losing to Adrian Mannarino of France 6-4, 6-7 (2), 7-6 (4).