World No.9 Madison Keys overcame some issues on serve to launch her Adelaide International title defence by ousting young qualifier Tereza Valentova 6-4 6-1 on Day 3 at The Drive.
Keys was broken twice in her first three service games on Centre Court and sprayed seven double faults in the opening set.
But once she problem-solved her faulty ball toss, the American couldn't have been more imperious in her dismissal of the 18-year-old Czech, marching into a quarterfinal meeting with rising Canadian Victoria Mboko.
"I think overall it was a pretty good match today," Keys said."Definitely got a little bit better in the second set, and kind of was able to run away with it.
"But she's (Valentova) a very talented young player, and I'm sure that we'll see much more of her."
Keys memorably followed her success in Adelaide 12 months ago by claiming her maiden Grand Slam a fortnight later in Melbourne.
The second seed was given a warm reception from the South Australian fans.
"I have always really enjoyed playing here," Keys said. "It's a great court on top of everything. It just feels like really great conditions. And then obviously having all of those really great memories is kind of icing on the cake."
Aussie Vukic moves on
Aleksandar Vukic capped a memorable 24 hours by following his stunning upset of seventh seed Stefanos Tsitsipas with a 6-2 7-6(5) win over fellow qualifier Andrea Vavassori.
Vukic's first serve was virtually untouchable early, before the Australian was forced to ward off a stiffer challenge from his crafty Italian opponent in the second set.
Vukic set up match point with back-to-back aces before punching his ticket into a quarterfinal date with second seed Tommy Paul when Vavassori double-faulted.
"Faced a different type of opponent today," Vukic said. "He's very tricky, plays mostly in the doubles, but is a very, very good singles player.
"He beat some very good players leading up to this. I knew it was going to be very tricky."
Quarterfinals set for Cristian and Paul
Daria Kasatkina racked up nine double faults and failed to hold her serve once as she was dismissed 6-4 6-0 by Romanian qualifier Jaqueline Cristian in the opening fixture on Centre Court.
Cristian's quarterfinal opponent will be Gold Coast wildcard Kimberly Birrell, who advanced when her scheduled second-round opponent Marketa Vondrousova withdrew with a left shoulder injury.
Paul secured his first tour victory since last year's US Open after downing good friend Reilly Opelka 6-4, 6-4 on Showcourt 1.
Forced to shut his 2025 season down after Flushing Meadows with a left foot issue, Paul looked fit and refreshed against his fellow American.
"I don't think he (Opelka) served his best today, but I did a great job of capitalising on his second-serve points," Paul said. "I thought from the ground, I played a pretty error-free match. I took care of my serve and that was the game plan coming in.
"The foot's all good, the body's all good, I'm happy with how my body is and I'm excited to get the year really going."