Stockholm - Top seed and former champion Tomas Berdych has beaten Dustin Brown of Germany 7-5, 6-3 to reach the quarter-finals of the Stockholm Open on Thursday.
The Czech, who had a bye into the second round, is coming off finals appearances in the last two weeks in Beijing and Shanghai.
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 US put away sixth-seeded Jeremy Chardy of France 7-6 (3), 6-3 to line up defending champion Grigor Dimitrov in the quarter-finals, and qualifier Matthias Bachinger of Germany hit 15 aces as he upset fifth-seeded Leonardo Mayer of Argentina.
Fourth-seeded Alexandr Dolgopolov of Ukraine faced Adrian Mannarino of France late.
Results on Thursday from the ATP Stockholm Open (x denotes seeding):
Tomas Berdych (CZE) bt Dustin Brown (GER) 7-5, 6-3
Marius Copil (ROM) bt Pierre-Hugues Herbert (FRA) 6-4, 6-3
Matthias Bachinger (GER) bt Leonardo Mayer (ARG x5) 7-6 (3), 6-7 (4), 6-3
Jack Sock (USA) bt Jrmy Chardy (FRA x6) 7-6 (7/3), 6-3