MUNICH: Defending champion Philipp Kohlschreiber and top-seeded Gael Monfils lost at the BMW Open on Thursday. Kohlschreiber, who had been going for an unprecedented fourth title at the clay-court tournament, failed to convert any of his three break points and lost to Horacio Zeballos of Argentina 7-6 (5), 6-4 in the second round. 'I can't be too hard on myself. He did well,' Kohlschreiber said. Monfils, who received a first-round bye, lost to Chung Hyeon of South Korea 6-4, 6-2. The 78th-ranked Chung will next play Martin Klizan of Slovakia, who upset sixth-seeded Mischa Zverev of Germany 6-2, 6-1 in 49 minutes. 'To be honest, I didn't have a chance against him,' said the older Zverev brother. Alexander 'Sascha' Zverev is through to the quarter-finals. Also, fourth-seeded Fabio Fognini lost to Argentine qualifier Guido Pella 6-3, 6-2. Pella will meet Zeballos in the quarter-finals.