MELBOURNE, Australia -- It all came so seemingly easy for Iga Swiatek last season -- two Grand Slam trophies, eight titles overall, a 37-match winning streak, a lengthy stay at No. 1 in the rankings.
Those accomplishments made everyone else expect constant greatness from Swiatek, which she can't do anything about. They also changed the way she approached big moments, and a 6-4, 6-4 loss to Wimbledon champion Elena Rybakina in the Australian Open's fourth round Sunday made Swiatek wonder whether she needs to reassess her outlook.
"I felt like I took a step back in terms of how I approach these tournaments, and I maybe wanted it a little bit too hard. So I'm going to try to chill out a little bit more," Swiatek said. "I felt the pressure, and I felt that 'I don't want to lose' instead of 'I want to win.' "
So there will not be a showdown between Swiatek and No. 7 seed Coco Gauff in the quarterfinals at Melbourne Park. Instead, it will be Rybakina taking on 2017 French Open champion Jelena Ostapenko, a 7-5, 6-3 winner against Gauff, with a semifinal berth at stake.
"I kept her under so much pressure," Ostapenko said.
Add Swiatek's loss to Week 1 exits by Ons Jabeur, Rafael Nadal and Casper Ruud, and this Australian Open marks the first Grand Slam tournament in the Open era -- which began in 1968 -- with the top two women's seeds and top two men's seeds all gone before the quarterfinals.
In other women's action Sunday, No. 3 Jessica Pegula got to the quarterfinals in Australia for the third year in a row by defeating 2021 French Open champion Barbora Krejcikova 7-5, 6-2. Pegula now plays 2012-13 Australian Open champion Victoria Azarenka, who returned to the final eight at Melbourne Park for the first time since 2016 by grabbing the last three games of a 4-6, 6-1, 6-4 victory over 87th-ranked Zhu Lin that ended at nearly 2:20 a.m. on Monday.
Both the 22nd-seeded Rybakina, a 23-year-old who represents Kazakhstan, and the 17th-seeded Ostapenko, a 25-year-old from Latvia, made it this far in Melbourne for the first time.
"There was moments in the match where I was getting frustrated, because I normally can problem-solve, but today I feel like I didn't have much answers to what she was doing," said Gauff, an 18-year-old from Florida who was the runner-up to Swiatek at the French Open last June.
"There was balls I was hitting deep, and she was hitting them on the line and hitting them back deep, over and over again," said Gauff, who wiped away tears during her news conference. "It's just one of those days that just didn't go my way and went her way."
One key: Ostapenko went 3-for-3 converting her break chances, and Gauff was just 1-for-8 in such situations.
Rybakina, meanwhile, used her big serve to produce a half-dozen aces, part of an overall 24-15 edge in total winners against Swiatek.
In men's results, 22-year-old American Sebastian Korda -- whose father, Petr, won the 1998 Australian Open -- reached his first Grand Slam quarterfinal by edging No. 10 Hubert Hurkacz 3-6, 6-3, 6-2, 1-6, 7-6 (10-7), unseeded Jiri Lehecka upset No. 6 Felix Auger-Aliassime 4-6, 6-3, 7-6 (2), 7-6 (3), and No. 18 Karen Khachanov eased past No. 31 Yoshihito Nishioka 6-0, 6-0, 7-6 (4).
Korda will meet Khachanov now, while Lehecka takes on No. 3 Stefanos Tsitsipas, who outlasted No. 15 Jannik Sinner 6-4, 6-4, 3-6, 4-6, 6-3 on Sunday night. Lehecka was 0-4 in Grand Slam matches until this tournament, while Tsitsipas was the runner-up at the 2021 French Open and is a three-time semifinalist at Melbourne Park.
Until Sunday, both Swiatek and Gauff looked fairly dominant for a week, winning every set they contested. Swiatek dropped a total of just 15 games, Gauff just 19, through three matches.
"For sure, when you play against No. 1, I think you have really nothing to lose. I knew that I had to be aggressive from the first ball because she's a great mover, and she defends really well," Rybakina said. "So I was trying to just attack her from the first ball, and it really worked well."