World No. 1 Iga Swiatek survived a major scare on Thursday, while men's No. 2 Carlos Alcaraz also battled through to the third round at the Australian Open as women's top-five seeds Elena Rybakina and Jessica Pegula crashed out.
Kick-starting a dramatic day five, Swiatek snatched a remarkable 6-4, 3-6, 6-4 victory over former finalist Danielle Collins in three hours and 14 minutes.
Four-time Grand Slam winner Swiatek was on the brink of a shock exit after being broken twice and falling behind 4-1 in the third set. But the resilient Pole dug deep as she capitalized on a nervous Collins and reeled off five straight games to clinch her 18th straight victory.
Zhang Zhizhen of China hits a return during the men's singles second round match Ugo Humbert of France and Zhang Zhizhen of China at the Australian Open tennis tournament in Melbourne, Australia, Jan. 18, 2024. (Photo by Chu Chen/Xinhua)
Swiatek, who sported a knee brace on her left leg, remains on course for a maiden triumph at Melbourne Park with her best previous finish being in 2022 when she lost in the semifinals to American Collins.
"It wasn't easy," Swiatek said. "I felt like I had the momentum going and then she started playing suddenly two times faster and I had no idea how to react to that for a couple of games. I came back, and I thought the only thing I could focus on was myself."
She will face unseeded Czech Linda Noskova next.
But a couple of Swiatek's rivals crashed out as her path opened up. Third seed and last year's tournament finalist Rybakina succumbed to Russian Anna Blinkova in the longest women's tiebreak in Grand Slam history.
Unseeded Blinkova finally clinched victory on her 10th match point to prevail 6-4, 4-6, 7-6 (20) in two hours and 46 minutes. She had to save six match points in an epic 42-point tiebreak that lasted 31 minutes.
The nerve-jangling back and forth had spectators jumping out of their seats and left the chair umpire laughing in disbelief.
"It was super tough. I just tried to stay focused," No. 57 Blinkova said. "I tried to be aggressive but my hands and legs were shaking. I tried to be calm... super happy to win."
Fifth seed Pegula also packed her bags after being upset by young French star Clara Burel 6-4, 6-2.
The defeat ended the American's bid to improve her Grand Slam record having never gone past the quarterfinals.
China's top-ranked player Zheng Qinwen beat Katie Boulter 6-3, 6-3 to book a last-32 clash with compatriot Wang Yafan, who defeated Emma Raducanu 6-4, 4-6, 6-4.
In the men's matches, Alcaraz equaled his best result in Melbourne after a 6-4, 6-7 (3), 6-3, 7-6 (3) win against unseeded Italian Lorenzo Sonego in breezy conditions.
But the two-time Grand Slam champion will be eyeing a much deeper run with Alcaraz deemed as top seed Novak Djokovic's biggest challenger.
"I'm really happy with my performance today. I think both of us played such a great level, high intensity," he said. "We put on a show, both of us, making good points and some hot shots as well. It was a great match."
The Spaniard overcame a second set stutter and had to fight through a tiebreak in the fourth set to book his spot in the last 32 against Chinese wildcard Shang Juncheng.
The 18-year-old Shang battled back from a set down to beat Indian qualifier Sumit Nagal 2-6, 6-3, 7-5, 6-4.
But Zhang Zhizhen, China's highest-ranked men's player, fell to 21st seed Ugo Humbert in a tough four-set match.
No.6 Alexander Zverev and 11th seed Casper Ruud were pushed to the limit, but both won fifth-set tiebreaks.
Eighth seed Holger Rune was a major casualty in the men's after losing in four sets to French wildcard Arthur Cazaux.
Djokovic and women's No. 2 Aryna Sabalenka will highlight third-round action on Friday.