Dayana Yastremska knocked off two -time Australian Open champion Victoria Azarenka 7-6 (6), 6-4 to start the final week of the major with her first trip to a Grand Slam quarter-final.
The 23-year-old Ukrainian ranked 93rd will play for the semi-finals against Czech teen prodigy Linda Noskova, who advanced to a career best after opponent Elina Svitolina was forced to quit after losing the first three games of their fourth-round match with back pain.
Yastremka sealed the upset against 18th seed Azarenka with a break for 4-3 and the second set and seized victory three games later as she sent a winning into the corner after just over two hours.
The outsider from qualifying rounds finished with 37 winners as she played through fatigue.
“Today I felt a little bit tired,” the winner said. “But I looked at my box and they were telling me to try and just play two shots (on each point).
“But I’m tired just standing here even if I’m pretending not to be.”
Yastremska’s previous best at a major was the Wimbledon fourth round five years ago.
“I need to breathe, my heart feels like it’s jumping out of my body. But I’m a fighter, that’s why I won this match.
“I like to play aggressive, but I don’t like making mistakes.”
Noskova, who knocked out world No. 1 Iga Swiatek in the third round, spent just 20 minutes on court before Svitolina had to quit their match.
“I got a spasm, a shooting pain in the last two points of the first game,” Svieolina said.
“I could not do anything, it completely blocked my back.
“It’s just very sad of course. I’ve never had anything like this before.
“It came out of nowhere, it felt like someone shot me in the back.”
