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.
In the UK, top seed Ashleigh Barty continued her procession through the Nottingham Open draw with a straight-sets win over Yingying Duan.
The world No.17, a quarter-finalist in the last two editions of the tournament, brushed aside the Chinese 28-year-old 6-3 6-2.
"I feel like I always play well in Nottingham," Barty said. "So hopefully it's third time lucky, and I can get one step farther in the tournament."
Her opponent in the last eight will be British world No.156 Katie Boulter, who claimed one of the best victories of her career against former US Open champion Sam Stosur.
The 21-year-old has made significant strides in 2018 and powered to a 7-6 (8-6) 6-1 victory over Stosur, the winner at Flushing Meadows in 2011.
"It's really exciting. It's a huge step for me," Boulter said. "She's a grand slam winner, and it's the first one of those that I've beaten. It was a really quick second set but I dug in really deep in the first. I thought I held my nerve really well and found a way to win."
Johanna Konta won an all-British battle against Heather Watson to join Boulter in the last eight.
It was a second meeting on the WTA Tour for Britain's top two female players and, like the previous one in Indian Wells last year, Konta came out on top.
The windy conditions made life difficult for both players but ultimately it was the extra power of Konta, who reached the Nottingham final 12 months ago, that made the difference in a 6-4 7-6 (7-5) victory.
Konta will face Slovenina Dalila Jakupovic in the quarters while defending champion Donna Vekic of Croatia recorded a 6-2 7-6 (8-6) win over Belarusian Vera Lapko and faces Germany's Mona Barthel.
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