"From the beginning, he served well and that's why it was close," Berdych said. "It was 4-4 and then I made my first break. Things started going my way after that."
In Saturday's semis, Berdych will face No. 3 Mikhail Youzhny of Russia.
Youzhny topped eighth-seeded Jurgen Melzer of Austria, 6-2, 7-6 (7-5) to record his 200th ATP career victory.
In Saturday's other semifinal, Kohlschreiber faces Baghdatis.