Top-ranked Jannik Sinner moved into the semifinals of the China Open with a 6-2, 7-6 (6) victory over Jiri Lehecka on Monday.
Just two days after the World Anti-Doping Agency announced it was seeking a ban of one to two years for the U.S. Open champion, who tested positive twice for an anabolic steroid in March, the 23-year-old Italian didn't appear distracted as he quickly got to grips with the No. 37-ranked Lehecka's serve in a dominant first set.
The defending champion faced two set points at 4-6 in the second-set tiebreak, but found a way to close out his 14th consecutive win and advance to a semifinal against either fifth-seeded Andrey Rubev or local favorite No. 96-ranked Bu Yunchaokete, who play later Monday.
"So happy how I handled a tough situation," Sinner said. "Feel like I still can improve a couple of things here so hopefully tomorrow is going to be that day when I feel better on the court."
Third-ranked Carlos Alcaraz advanced to the China Open semifinals for the second straight year after an impressive 7-5, 6-2 victory against Karen Khachanov on Monday.
The 21-year-old Spaniard was characteristically relentless from the baseline and ground down the No. 27-ranked Khachanov's service games and converted four of 12 service break opportunities to win in 96 minutes.
"I always try to put some pressure when they're serving just to in a certain way tell them that I'm going to be there," Alcaraz said. "If they want to win the service game or to beat me, they have to accept the battle and playing a really good tennis. For me, it's what I'm trying to show them all the time."
It was Alcaraz's 46th win of the season and the victory allowed the reigning French Open and Wimbledon champion to climb back above the absent Alexander Zverev into second place in the ATP live rankings.
Alcaraz will face Daniil Medvedev in the semifinals, after the fifth-ranked Russian beat Flavio Cobolli of Italy 6-2, 6-4.
Medvedev, still looking for his first title of the year, made 16 fewer unforced errors than the Italian and converted four of his eight breakpoint opportunities as he closed out a solid 88-minute victory.
Earlier, Andrey Rublev beat Alejandro Davidovich Fokina 6-4, 7-5 in a match that was carried over from Sunday because of a rain delay.
No. 6-ranked Rublev had six aces and 21 winners to extend his career record against Davidovich Fokina to 5-0.
The fifth-seeded Russian played local favorite No. 96-ranked Bu Yunchaokete in the quarterfinals later Monday.
Information from The Associated Press contributed to this report.