Jerzy Janowicz advanced to the quarterfinals of the Stuttgart Open by beating second-seeded Grigor Dimitrov 7-6 (4), 6-3 Thursday.
Despite 16 aces, Dimitrov failed to convert any of his three break-point chances.
Janowicz will next play either Benoit Paire or Peter Gojowczyk.
Third-seeded Tomas Berdych also advanced, beating Bernard Tomic 7-6 (4), 6-2. Berdych will next face Feliciano Lopez in the quarterfinals. Lopez defeated Jeremy Chardy 6-3, 3-6, 6-2.