Russia s Daniil Medvedev makes a forehand return to Serbia s Miomir Kecmanovic during their Round of 16 match at the Adelaide International Tennis tournament in Adelaide, Australia, Wednesday, Jan. 4, 2023. (AP)
Medvedev, runner-up at the last two Australian Opens, blew away the new year cobwebs with a 6-0, 6-3 romp over Serbian Miomir Kecmanovic.
It came a day after the 2021 US Open champion had to save nine set points against first-round opponent Lorenzo Sonego before the Italian retired hurt.
"I think it was a great match. Miomir is a tough opponent, a high-ranked player so there are no easy guys left in Adelaide," third seed Medvedev said of the 29th-ranked Serb.
"I'm not sure there were any (easy opponents) from the first round, so really happy to be through, happy with my level."
The world number seven dropped just 12 points in a whirlwind 28-minute opening set before closing out the match comfortably.
Next up is eighth seed Khachanov, who eased past Britain's Jack Draper 6-4, 6-2.
Rising Japanese star Yoshihito Nishioka also went through. Having dispatched fifth seed Holger Rune in the first round, he backed up to beat American Mackenzie McDonald 6-4, 6-3.
His reward is a last eight clash with either Australian qualifier Alexei Popyrin, who stunned second seed Felix Auger-Aliassime on Monday, or American Marcos Giron.
World number five Sabalenka came back from 1-5 down in the first set to fight past dogged Russian Liudmila Samsonova 7-6 (10/8), 7-6 (7/3) and make the quarter-finals.
She will meet Marketa Vondrousova for a place in the last four after the Czech player's dominant 6-0, 6-4 dismissal of Estonian Kaia Kanepi.
"When you're 1-5 down there's nothing to lose and you just go for your shots without thinking," Sabalenka said of clawing back against a player who collected trophies in Tokyo, Cleveland and Washington last year to crack the top 20.
"That really helped me to stay in the set, keep fighting and trying. She's an incredible player with a huge serve, so was tough."
She lost to the 20th-ranked Samsonova in three sets in Guadalajara last October before rounding out a stellar season, which included a run to the US Open semi-finals.
Sabalenka had a first-round bye but notched a pair of doubles wins alongside Lidziya Marozava to kickstart her Adelaide campaign.
Vondrousova was keen to move on from a disjointed 2022 in which she missed six months due to a wrist injury, making her first quarter-final since reaching the last four in Dubai almost a year ago.
"I'm just so happy to be back playing. It was a very tough time when I didn't play, so yeah, I'm just very happy to be playing at this level," she said.
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