Fifth-seeded Bernard Tomic cut short the comeback of German veteran Tommy Haas and reached the quarter-finals of the Mercedes Cup with a 7-6 (8-6) 6-2 victory on Thursday.
The 37-year-old Haas played his second match after missing more than a year with a shoulder injury.
Tomic saved two set points and then won the first 11 points of the second set as he quickly broke Haas’ serve twice for a decisive lead.
The Australian will next face either top-seeded Rafael Nadal or Marcos Baghdatis.
German qualifier Mischa Zverev continued his good run in the grass-court event, beating Andreas Seppi of Italy 6-2 6-4 for a place in the last eight.