Nick Kyrgios has returned from a two-month absence to beat Germany's Maximilian Marterer at the Stuttgart Open.
The fourth seed, who missed the French Open with an elbow injury, received a bye in the first round and reached the quarter-finals with a 6-4 4-6 6-3 victory.
There looked to be nothing wrong with Kyrgios's serving arm as he banged down 20 aces on the grass and he delighted fans with a trademark trick shot that proved a turning point in the decider.
With Marterer serving at 2-3, Kyrgios played a shot through his legs for a winner and it appeared to ruffle Marterer who then made two unforced errors to drop serve.
Kyrgios then held his next two service games to book a clash with Spanish left-hander Feliciano Lopez.
Lopez, runner-up last year before going on to win the Queen's Club title, beat Frenchman Gilles Simon 7-6 (8-6) 6-4.
"This is very important for me, to have weeks on grass. It's a very unique surface. You play only two, three weeks a year ... it's so important to get matches, to get hours on the grass and (you get more) when you win," Lopez said.
Tomas Berdych beat Benoit Paire 7-6 (6-3) 6-4 to end his five-match losing streak and reach the quarter-finals.
The third-seeded Czech dropped just six first-serve points and saved the only break he faced.
Berdych next faces Milos Raonic, who beat Marton Fucsovics 6-2 6-4. The seventh-seeded Canadian is going for his first title on grass.
Top seed Roger Federer will be back in action on Friday when he plays Guido Pella.
