Gael Monfils made a successful start to his Mercedes Cup campaign, beating Andreas Haider-Maurer in Stuttgart.
The Frenchman hit 18 aces in the 7-6 (7/6) 7-6 (7/5) second-round success, which took 87 minutes.
Monfils was playing his first grass-court match of the season after reaching the fourth round of the French Open.
He will face sixth seed Philipp Kohlschreiber in the quarter-finals, following the German's 6-4 6-4 success over Jerzy Janowicz.
Eighth seed Viktor Troicki saw off Alexander Zverev 6-3 6-7 (6/7) 6-3 to book a quarter-final clash against Sam Groth, who edged out third seed Feliciano Lopez 3-6 7-6 (7/5) 7-6 (7/6).
Source: PA
