Simone Bolelli of Italy defeated second-seeded Florian Mayer of Germany 6-2, 7-6 (4) to reach the quarterfinals of the Bet-at-Home Cup on Wednesday.
Mayer was looking for his third straight quarterfinal after reaching the last eight at Wimbledon and Hamburg.
Bolelli will next play Martin Klizan, the fifth-seeded Slovak who defeated countryman Pavol Cervenak 6-4, 6-4.
Lukas Rosol of the Czech Republic beat Antonio Veic of Croatia 6-3, 5-7, 6-3 to set up a quarterfinal against either top-seeded Philipp Kohlschreiber of Germany or Attila Balazs of Hungary.
Balasz led Kohlschreiber 3-0 in the opening set when play was suspended for the day because of rain.
In another unfinished second-round match, Wayne Odesnik of the United States led Jurgen Zopp of Estonia 5-7, 7-5, 3-0.