Top-ranked Jannik Sinner put the controversy of his doping case behind him, advancing to the China Open semifinals alongside Carlos Alcaraz and Daniil Medvedev on Monday.
The defending champion will face Chinese wild card Bu Yunchaokete after securing a 6-2, 7-6 (8-6) victory over Jiri Lehecka, marking his 14th consecutive win.
The 23-year-old is back in the spotlight as the World Anti-Doping Agency (WADA) announced Saturday that it is pursuing a ban of up to two years after he tested positive for traces of the steroid clostebol twice in March.
The International Tennis Integrity Agency (ITIA) cleared the Italian of wrongdoing in August and allowed him to continue playing. Weeks later, he won the U.S. Open for his second major title.
The ITIA accepted Sinner's explanation that the drug entered his system when his physiotherapist used a spray containing it to treat a cut and then provided massage and sports therapy to the player.
WADA has appealed the case to the Court of Arbitration for Sport.
"For sure I had sleepless nights during this time. Now again, it's going to be not easy," he said on Monday, admitting that "this is a very difficult moment."
On the tennis court, Sinner saved two set points in the second set to clinch victory over the 37th-ranked Lehecka from the Czech Republic.
Now in his 10th semifinal of the season, Sinner will be the heavy favorite over Bu in what will be the biggest match of the 96th-ranked Chinese player's life.
The 22-year-old Bu is the lowest-ranked China Open semifinalist since 2008.
Four-time Grand Slam champion Alcaraz plays last year's runner-up Medvedev after emerging from a tense first set to defeat Russian seventh seed Karen Khachanov 7-5, 6-2.
Russian third seed Medvedev beat unseeded Italian Flavio Cobolli 6-2, 6-4.
"When he's in the zone, he's probably the best player in the world," Medvedev said of the second-seeded Alcaraz. "I feel like now he's in the zone, so it's a great test for me."
Osaka vs. Gauff 'battle'
In the women's draw, Naomi Osaka set up a last-16 clash with Coco Gauff, while top seed Aryna Sabalenka and Olympic champion Zheng Qinwen both sailed through.
Four-time major champion Osaka defeated American Katie Volynets 6-3, 6-2 and faces American fourth seed Gauff in a showdown of former U.S. Open titleholders.
"It's definitely going to be a battle – who wants to take control of the point first," said Osaka, a former No. 1 now ranked 73rd. "And I think it's going to be me."
Osaka is playing her first tournament under Patrick Mouratoglou, the Frenchman best known for being the longtime former coach of Serena Williams.
The 26-year-old Japanese player won four majors from 2018 to 2021 – the U.S. Open and Australian Open, both twice. She is also a former winner in Beijing and has said she feels at home on the hard courts of the Chinese capital.
However, Osaka has struggled for consistency since returning to tennis in January after the birth of her daughter, Shai. Her best results after becoming a parent have been two quarterfinal appearances.
World No. 2 Sabalenka will be tough to stop after the U.S. Open champion swatted aside Ashlyn Krueger 6-2, 6-2 for her 14th victory in a row. She plays another American next in Madison Keys.
Zheng, the home hero playing in China for the first time since winning gold in Paris, rolled over Nadia Podoroska of Argentina 6-3, 6-2.
Jasmine Paolini became the biggest casualty so far when the third seed was beaten 6-4, 6-0 by 31st-seeded Magda Linette.