Australia's Nick Kyrgios blasted new world number one Rafael Nadal 6-2, 7-5 on Friday, winning twice in one day to reach the WTA and ATP Cincinnati Masters semi-finals.
As defending champion Karolina Pliskova won twice in one day for the third time this season to tighten her grip on the world number one ranking, Kyrgios stole the show by overpowering the 15-time Grand Slam champion after each had won earlier.
"A kid playing Nadal on center court, that's where your best has to come out," Kyrgios said. "Performance like today, I'm seeing progress."
Kyrgios, ranked 23rd, faces Spain's David Ferrer for a finals berth. Bulgaria's 11th-ranked Grigor Dimitrov plays American John Isner in Saturday's other semi-final.
Nadal, who won his 10th French Open title in June, was assured of moving into the top ranking on Monday for the first time since July 2014 when Roger Federer withdrew from Cincinnati with a back injury.
Kyrgios was up a double break in 10 minutes, seizing the chance to make a between-the-legs showoff shot on his way to a 4-0 lead, drawing boos from the crowd.
"I was just doing it for a gag," Kyrgios said. "I just felt like doing it. My friends who were watching were laughing so they liked it I guess."
He took the first set in 25 minutes, dropping only three points on his serve, then broke Nadal in the fifth game of the second set. The Aussie served for the match in the 10th game but double faulted on his third match point and Nadal broke back.
"I had the match on my racket and tightened up," Kyrgios said.
But the 22-year-old broke again to lead 6-5 and this time end matters with his 10th ace after 80 minutes, improving to 2-2 all-time against the 31-year-old Spaniard.
"I started the match very low and I played a very bad game in the second set when he break me," Nadal said. "I was able to get some points and get back in the match but then I played a terrible game. It was a bad match for me. Congrats to him."
- 'No excuses' for Nadal -
Nadal took only 6-of-20 second serve points and won only five off his foe's first serve.
"No excuses. Nothing at all," Nadal said. "If I don't play well I can't win against a player like Nick."
Earlier, Kyrgios defeated Croatia's Ivo Karlovic 4-6, 7-6 (8/6), 6-3 and Nadal downed compatriot Albert Ramos-Vinolas 7-6 (7/1), 6-2 in rain-postponed matches.
Kyrgios, who matched his best ATP Masters runs from Miami the past two years, seeks his fourth career title after 2016 trophies at Marseille, Atlanta and Tokyo.
And he served notice for the US Open, where he has never reached the fourth round. The year's last Grand Slam starts August 28.
Ferrer upset Austria's eighth-ranked Dominic Thiem 6-3, 6-3 while Isner fired 25 aces in beating American wildcard Jared Donaldson 7-6 (7/4), 7-5 and Dimitrov downed Japan's Yuichi Sugita 6-2, 6-1.
- Pliskova, Halep seek No. 1 -
Pliskova, fighting to hold off Romania's Simona Halep atop the rankings, first ousted Italian qualifier Camila Giorgi 6-3, 4-6, 6-0 in a rain-postponed match.
With only two hours between matches, the 25-year-old Czech defeated Denmark's fifth-ranked Caroline Wozniacki 6-2, 6-4 to book a Saturday semi-final against Wimbledon champion Garbine Muguruza.
"I feel pretty good," Pliskova said. "I recover well, so definitely I will be ready."
Second-ranked Halep eliminated British seventh seed Johanna Konta 6-4, 7-6 (7/1) to book a semi-final date with US wildcard Sloane Stephens.
"I played the best match so far," Halep said. "I could move well. So I feel the rhythm. It's back. So I'm positive again."
Pliskova's two-in-one effort, matching feats on her way to Eastbourne and Doha titles, means Halep must capture the crown to swipe the top spot in Monday's rankings.
"Whatever comes I will just take it," said Pliskova. "Even if I would be second coming to the US Open, it's still better than I was last year. So no pressure about being world number one."
Sixth-ranked Spaniard Muguruza ousted Russian eighth seed Svetlana Kuznetsova 6-2, 5-7, 7-5.