A motivated Andy Murray notched the 600th victory of his career with a 6-3, 6-2 defeat of Kevin Anderson which ended Thursday's upset jinx at the Cincinnati Masters.
Murray, the top seed, survived nicely four days after winning a second Olympic gold medal in Brazil. Rivals Stan Wawrinka and Rafael Nadal, the second and third seeds, were both eliminated earlier in the third round.
Second seed Wawrinka crashed out to this week's doubles partner Grigor Dimitrov 6-4, 6-4. Injured and aching Nadal limped out, a 6-1, 6-3 victim of teenaged Borna Coric.
Wawrinka skipped Rio with back pain but said his fitness has not been an issue for a week or more.
The Swiss produced 28 unforced errors in the loss lasting for less than 90 minutes against Dimitrov.
Murray was particularly pleased to have set one of his many career records in Cincinnati.
"It was good to do it here, where I got a wild card when I was 18. I also won my first Masters 1000 title here (2005). To win my 600th here is cool.
"I've played a lot of matches, 600 is obviously a lot. I never expected to be in this position when I started."
Murray takes a perfect 4-0 record into his quarter-final against Bernard Tomic, who upset fifth seed Kei Nishikori 7-6 (7-1), 7-6 (7-5).
Nadal's performance - among the heaviest defeats of his career - was punctuated by a visit from the trainer after the opening set. It was in sharp contrast to the Spaniard's gold-medal doubles success last weekend.
Nadal was beaten in 2008 by Mikhail Youzhny in the Chennai final 6-0, 6-1 and went down in the Doha final last January to Novak Djokovic 6-1, 6-2.
"After two months and a half and with an injury in the wrist, the normal thing is try to come back a little bit slower," Nadal said.
He said he was "at the limit" after Rio and it was clear he was not ready, but "it was not easy to take the decision to not come here after the Olympics."
He added: "I didn't want to be back home. I spent enough time there the last three months. I needed to keep practising, keep playing."
Nadal was bothered by a left elbow injury and a too-tight strapping on his left ankle. The 30-year-old missed two months with a left wrist injury and was playing his first Tour event since the French Open.
Nadal had trouble mustering energy in the 72-minute upset loss to Coric as Olympic fatigue seemed to catch up with him.
At one point the 19-year-old Coric, ranked 49th, won 10 games in a row to take the opening set and grab a 4-0 lead in the second,
Nadal now has 11 days to recover and prepare for the US Open after missing two summer months of play since quitting Roland Garros with his left wrist injury.
Milos Raonic, seeded fourth, put out Yuichi Sugita 6-1, 3-6, 6-1, with the winner trated on a hip during the victory.
Steve Johnson took the top American ranking from John Isner through a knockout of seventh seed Jo-Wilfried Tsonga 6-3, 7-6 (8-6). Austrian eighth seed Dominic Thiem advance don a walkover when Gael Monfils withdrew with back pain.
In the women's third round, second seed Angelique Kerber moved a step closer to taking the WTA number one ranking as she beat Barbora Strycova 7-6 (7-5), 6-4.
Rio silver medallist Kerber could take over the top of the table from Serena Williams if she can win the weekend Cincinnati title
Third seed Simona Halep, 2015 runner-up, scored a 6-1, 6-2 defeat of Australian Daria Gavrilova. Number seven Svetlana Kuznetsova elimianged Swiss Timea Bascinszky 6-2, 3-6, 6-2.