Beijing - Alexander Zverev smashed his racquet in frustration after he was the victim of a surprise three-set defeat to world number 61 Malek Jaziri at the China Open on Thursday.
With his coach Ivan Lendl looking on stony-faced, the German prodigy exited in the last 16 in Beijing, the indefatigable Tunisian Jaziri winning 7-6 (7/4), 2-6, 6-4.
Zverev, 21, the second seed touted as a future multiple Grand Slam winner, reacted by whacking his racquet on the floor, bending it badly out of shape.
He then dished out more punishment, flinging it at his courtside chair as he trudged off.
The veteran Jaziri, 34, faces Nikoloz Basilashvili of Georgia in the last eight on Friday.
Fourth seed Fabio Fognini of Italy remains on course for a fourth title this season after he swatted away Russia's Andrey Rublev 6-4, 6-3.
Top seed Juan Martin del Potro plays unseeded Serbian Filip Krajinovic and will be strong favourite in the Chinese capital with Grigor Dimitrov and now Zverev both out.
In the women's draw, Aryna Sabalenka said that a pep talk from her coach warning her to stop being "crazy" was behind her dumping holder Caroline Garcia.
The 20-year-old, who grabbed the biggest win of her career with the Wuhan Open title last week, was staring defeat in the face on Beijing's increasingly chilly outside hard courts.
But roared on by a cheering squad decked out in matching purple and white jackets, the world number 16 from Belarus fought back to force a second-set tie break, and from there a deciding set.
With the fourth seed Garcia visibly wilting under the Belarusian's barrage, Sabalenka surged to the finish in a 5-7, 7-6 (7/3), 6-0 win and a place in the quarter-finals.
There she will meet China's unseeded Wang Qiang - herself in the form of her life and a surprise 6-4, 6-4 winner over Karolina Pliskova.
Sabalenka, whose reputation is growing fast, said she was almost lost for words after what was the best match of the tournament so far.
"I was really lucky that I won the second set. After that I don't know what happened with her, but she didn't run that well like the first and second set," said the powerful Sabalenka.
"No words to explain what happened today, how happy I am with this win."
Sabalenka - 111th in the world this time last year - said her coach Dmitry Tursunov had given her a minor dressing-down mid-match as her emotions threatened to get the better of her.
"He was just saying like, 'Come on, keep calm, you're too crazy on court.
"'Nobody is dying here, it's just tennis, try to enjoy it.'"
Naomi Osaka said an improvement in her focus is behind a run of success that culminated in winning the US Open.
The 20-year-old, who stunned Serena Williams to win her maiden Grand Slam last month, was devastating against 10th seed Julia Goerges, winning 6-1, 6-2 in 65 minutes.
The Japanese will face home hope Zhang Shuai after she pulled off a shock in defeating three-time Grand Slam champion Angelique Kerber.
The world number six Osaka said: "On the court I have to think 'focus' because it's not something that's natural to me.
"It's something that I've been working on throughout this whole year and I think it finally clicked, or at least it's more consistent."
Results from the WTA/ATP China Open in Beijing on Thursday (x denotes seed):
Zhang Shuai (CHN) bt Angelique Kerber (GER x3) 6-1, 2-6, 6-0
Naomi Osaka (JPN x8) bt Julia Goerges (GER x10) 6-1, 6-2
Wang Qiang (CHN) bt Karolina Pliskova (CZE x7) 6-4, 6-4
Aryna Sabalenka (BLR) bt Caroline Garcia (FRA x4) 5-7, 7-6 (7/3), 6-0
Katerina Siniakova (CZE) bt Kiki Bertens (NED x11) 6-4, 6-3
Caroline Wozniacki (DEN x2) bt Anett Kontaveit (EST) 7-5, 6-4
Fabio Fognini (ITA x4) bt Andrey Rublev (RUS) 6-4, 6-3
Marton Fucsovics (HUN) bt Marco Cecchinato (ITA x8) 6-4, 6-2
Nikoloz Basilashvili (GEO) bt Fernando Verdasco (ESP) 7-6 (7/3), 6-4
Malek Jaziri (TUN) bt Alexander Zverev (GER x2) 7-6 (7/4), 2-6, 6-4