After struggling with neck pain in his opening match, Novak Djokovic was back to somewhere near his best at the Western & Southern Open.
Yet fellow greats Serena Williams and Andy Murray were unable to replicate his winning ways, with both bowing out in later matches on Tuesday.
World No.1 Djokovic improved his win-loss record to a flawless 20-0 in 2020, thanks to a 6-2 6-4 win over American wildcard Tennys Sandgren.
The victory sent him through to the quarterfinals where he will face German Jan-Lennard Struff, who upset No.7 seed David Goffin 6-4 3-6 6-4.
In other men's results, defending champion Daniil Medvedev and eighth seed Roberto Bautista Agut joined Djokovic in the quarterfinals while No.6 seed Matteo Berrettini was overpowered by American Reilly Opelka.
Fourth seed Stefanos Tsitsipas stopped John Isner in two tiebreaks while former world No.3 Milos Raonic hit Murray off the court, beating the three-time Grand Slam champion 6-2 6-2 and dropping just three points on his first serve.
Also advancing to the last eight in New York – the tournament has been relocated from its usual venue in Cincinnati – were Naomi Osaka and Victoria Azarenka.
Osaka, seeded fourth, blasted pasted Dayana Yastremska 6-3 6-1 in just 70 minutes, while Azarenka recovered from 4-1 down in the second set to beat Alize Cornet 6-4 7-5.
Williams looked set to join them when she led Maria Sakkari 7-5 5-3, and later 4-1 in the second-set tiebreak, in the night match on Grandstand court.
Serena said she's putting herself in situations in matches she shouldn't be in, and likened it to dating a bad guy she knows she shouldn't be dating.
— Reem Abulleil (@ReemAbulleil) August 26, 2020
But she was unable to put the 13th seed away, increasingly hampered by cramp as she ultimately slumped to a 5-7 7-6(5) 6-1 loss.
Djokovic flawless in 2020
Djokovic broke Sandgren twice in the opening set and built a commanding 6-2 4-2 lead.
Sandgren made Djokovic work harder in the closing stages, forcing the top seed to rebound from 0-40 in the eighth game and then saving five match points in the next game when serving to stay in it.
Yet with a 5-4 lead, Djokovic stepped up to the line and held at love to seal victory in under 90 minutes.
Djokovic said he was “pleasantly surprised” by how his neck – which required treatment during his opening-round win over Ricardas Berankis – had recovered and that he was “closest to (a) painless neck as I can be”.
“I'm feeling very good. And that has positively obviously reflected on my game today,” said the Serb, who has enjoyed the second-best start to a season in his career.
Djokovic also did not rule out going the entire year undefeated.
“Look, anything is possible,” he said. “I don't want to count that out, I mean, especially because of the fact … we don't know how the post-U.S. tour season is going to look like, whether we are going to play, whether there is going to be another lockdown in Europe or not. We are hoping not.
“Right now it's not something I'm thinking about. It's not my goal, actually, to go unbeaten, but I wouldn't complain if I do (smiling).”
Osaka, Azarenka into quarters
Tuesday’s victory over Yastremska marked Osaka’s second win in as many days, after the Japanese star beat Karolina Muchova in three sets in her opening match.
She was in even more devastating form against the Ukrainian, smacking eight aces while keeping her unforced error tally to a tidy 14.
Osaka, a two-time Grand Slam champion, next faces 12th seed Anett Kontaveit for a place in the semifinals.
“I don't have expectations of myself right now, because, I mean, I haven't played in a really long time. I would just say I expect myself to behave a certain way, which is positively,” she said.
“I know I have been training really hard and I have been playing really good in LA, so I could only hope to play well here.
“I feel like I'm not playing at the level I really want to right now, but I'm building up towards it.”
Osaka revealed following her opening-round win that she was playing without shoulder pain for the first time since winning Beijing in October 2019, having used the coronavirus-enforced break to heal the injury.
Azarenka, who like Osaka is a two-time major winner, reached her first WTA quarterfinal since Rome in May last year.
Her victory over Cornet was her third consecutive straight-sets win at Flushing Meadows; earlier in the tournament she beat Donna Vekic and Caroline Garcia.
She improved her head-to-head record against France’s Cornet to 7-0.
Other women's winners on Tuesday were No.8 Johanna Konta, Ons Jabeur and qualifier Jessica Pegula, who upset fifth seed Aryna Sabalenka.
Pegula has now won five matches in a row in New York, and, after stopping Jennifer Brady and Amanda Anisimova earlier in the tournament, will play 14th seed Elise Mertens for a semifinal berth.