Ash Barty finally lost her serve – but not the match – to reach the quarterfinals at the Australian Open for the fourth consecutive season.
The world No.1 defeated a resurgent Amanda Anisimova 6-4 6-3 to move within three matches of becoming the first Australian woman to win her home Grand Slam since Chris O'Neil in 1978.
Barty hasn't dropped a set this fortnight or indeed a match this year, which is ominous for the rest of the field, including next challenger Jessica Pegula.
Anisimova did end Barty's streak of 63 straight service holds, but couldn't engineer another stunning upset after ousting defending champion Naomi Osaka on Friday.
Sunday's outcome at Rod Laver Arena mimicked the circumstances of their lone previous tussle at the 2019 French Open.
Anisimova entered by knocking off the defending champion, Simona Halep in that case, prior to exiting to Barty from a set and break up.
Barty, who went on to win the Roland Garros title for her maiden major, wasn't that close to defeat on this occasion.
Her first serve percentage wobbled at times, but she concluded with seven aces and 78 per cent first serve points won. Contrast 23 winners to 17 unforced errors, and her stats made for pleasant reading.
"She's got an exceptional game that puts you under the pump right from the get go," Barty said in her on-court interview.
"It was nice to be able to hold firm tonight and bring the points back into my patterns more regularly and big ones when it mattered most.
"She’s an incredible athlete and competitor. One of her best attributes is that she's able to turn up point after point after point.
"It's just nice to see her back playing her best tennis. She's a champion and she’s going to be in deep stages at a lot of majors," Barty added of Anisimova, who was understandably devastated when her father died in 2019.
Anisimova thwarted danger in the opening game, saving a break point. A "come on!" at deuce signalled the 20-year-old's intent.
Barty's serve came under threat in the fourth game. How Anisimova rued her second-serve return long, though Barty subsequently erred on two returns on two break chances at 2-2.
Barty drew first blood at 3-3, her all-around game on display. An angled forehand return dragged Anisimova wide before she finished with a backhand slice winner on the first point.
Another backhand slice winner made it 0-40, and Barty broke through when Anisimova's forehand sailed long.
Agonisingly for Anisimova, a second-serve backhand return rocketed long on another break chance in the ensuing game, leading to the world No.60 to squat down and tap her racquet onto the court.
Her first serve percentage hovering slightly above 55 heading into the 10th game, Barty delivered four first serves – and good ones – on the way to a love hold.
Anisimova rallied from a set down against Osaka, bending but not breaking as the Japanese megastar applied early pressure, and she would need to repeat the feat to send the match to a decider.
She saved a break point after leading 40-0 on serve, which perhaps unsettled Barty more than an easier Anisimova hold would have done.
At least one Australian in the crowd had to be pleased – her coach Darren Cahill. He was even happier when Anisimova broke for 2-0.
Anisimova sought breathing space in what felt like a pivotal sequence, yet Barty responded immediately.
Barty produced an ace to save another break point, Anisimova later falling to the court in dismay when a forehand at deuce misfired with her opponent stranded.
There would turn out to be more angst for Anisimova at 3-3. On top of the net with a simple-looking smash at 40-15, her drive powered well long. Ouch. It cost her dearly, as Barty broke for 4-3. Anisimova never recovered as Barty surged.
Anisimova lost her first match of the 2022 campaign, having triumphed at Melbourne Summer Set 2.
Barty wasn't sure if she had played Pegula, but she has, leading 1-0 in their duels – downing the American at Roland Garros in 2019, too.
A good omen?