The Russian-turned-Kazakh has spoken of her frustration at not being scheduled on the main courts since her success at the All England Club and, on Rod Laver Arena, she produced a big-stage performance to win 6-4 6-4.
Rybakina, who would be in the top 10 had Wimbledon offered ranking points, dropped only six points on her first serve during the match and recovered from 3-0 down against a frustrated Swiatek.
The result, coupled with defeats for Ons Jabeur, Rafael Nadal and Casper Ruud, means for the first time in the open era, the top two seeds in both the men’s and women’s draws have lost before the quarter-finals.
While it is a big shock, Swiatek is not as dominant on hard courts as she is on clay and, although she has talked here of not expecting herself to win every match, it is clear the Pole finds it difficult to temper those expectations.
“For sure the past two weeks have been pretty hard for me,” said Swiatek, who won the French and US Opens last year.
“So I felt today that I don’t have that much to take from myself to fight even more. 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.
“I felt the pressure, and I felt that I don’t want to lose instead of I want to win. So that’s, I think, a base of what I should focus on in the next couple of weeks.”
This was a meeting between the only two current active female grand slam champions, and Rybakina made the perfect start by breaking Swiatek’s serve from 40-0.
Swiatek, who had received a warning before the start for taking too long to be ready to play, pulled back to 2-2 but the flatter hitting of Rybakina was paying dividends on a warm, sunny day in Melbourne and she forged ahead again to lead 4-3 and took the opening set.
Swiatek looked set to mount a comeback when she broke the Rybakina serve in the second game of the second but back came the 22nd seed.
Swiatek had never quite looked comfortable and she was unable to withstand the pressure in the ninth game, with Rybakina breaking and then serving out the match to love to reach the quarter-finals at Melbourne Park for the first time.
I felt the pressure, and I felt that I don't want to lose instead of I want to win
“Usually when I come back from being down, I’m able to hold that momentum,” said Swiatek. “Today I lost it. For sure she forced that as well, so congrats to her.
“I think it’s going to be motivating for me, and I’m pretty sure that I’m going to play the next tournaments with something to focus on, something to work on, and I think I’m going to go forward. So I think it’s OK.”
In the last eight, Rybakina will play a resurgent Jelena Ostapenko, who powered her way to a 7-5 6-3 victory over seventh seed Coco Gauff.
A surprise winner of the French Open in 2017 aged 20, Ostapenko has struggled in recent years but last season saw her climb back up the rankings and she is through to this stage of a grand slam for the first time since reaching the Wimbledon semi-finals in 2018.
The Latvian, now 25, insisted she had kept believing in herself, saying: “My life changed a lot, so I needed a few years to really get used to what happened because I was really young. I always knew and believed in my game. If I play well, I can beat almost anyone.”
Ostapenko simply had too much power for Gauff, who is one of the best defenders on tour but was unable to land her big first serve as often as she needed and paid the price.
It was a first defeat of the season for the 18-year-old following her title in Auckland and Gauff, who is still playing in doubles, shed tears of disappointment in her press conference.
“I think it’s because I worked really hard, and I felt really good coming into the tournament, and I still feel good,” she said. “I feel like I’ve improved a lot. But, when you play a player like her and she plays really well, it’s like there’s nothing you can do.”