Ostapenko said, “I knew she was such a great player, super young and she was playing really well, but I really had nothing to lose.”
“I just went out there and tried to do my best and tried to fight for every point, and made it tough for him, and I’m really happy with the way I played.”
Ostapenko, whose last Grand Slam quarterfinal came at Wimbledon in 2018, has endured some tough injury-plagued years since then and had never beaten a top 10-ranked player at the Australian Open.
“I was trying to stay positive all the time,” Ostapenko said. “And I knew I had to play aggressively, even if I missed a few balls.”
Third seed Jessica Pegula and in-form fifth seed Aryna Sabalenka now have women to beat as they both chase maiden Grand Slam titles.
American Pegula will face 20th seed Barbora Krejcikova in the fourth round on Sunday.