Melbourne (AFP) - Top seed Iga Swiatek and a tearful Coco Gauff both crashed out in straight sets in the last 16 on Sunday on another day of shocks at the Australian Open.

Swiatek’s defeat to Elena Rybakina makes it the first Grand Slam in the Open era – since 1968 – to lose the top two seeds in the men’s and women’s draws before the quarter-finals.

There was no such trouble for Jessica Pegula, however, the American third seed surging into the last eight with a 7-5, 6-2 win over former French Open champion Barbora Krejcikova.

Wimbledon champion Rybakina swept past the 2022 French and US Open winner Swiatek 6-4, 6-4 in 1hr 29min at a stunned Rod Laver Arena in Melbourne.

Moscow-born Kazakh Rybakina, seeded 22, moves on to a last-eight encounter with Jelena Ostapenko.

The Latvian 17th seed provided the second upset of a crazy few minutes by knocking out seventh seed Gauff 7-5, 6-3 on neighbouring Margaret Court Arena.

The 18-year-old Gauff broke down in tears during an emotional post-match press conference.

World number one and hot favourite Swiatek admitted that Rybakina deserved to win.

“I felt the pressure,” Swiatek, 21, said. “I felt that I didn’t want to lose instead of wanting to win.”

Swiatek, who dominated women’s tennis last year and is already a three-time major champion, added: “I felt today that I don’t have that much left 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.”

Swiatek follows second seed Ons Jabeur out the Melbourne exit door, the Tunisian having gone out in the second round in another surprise.

The American Gauff had been favourite to defeat Ostapenko, the 2017 French Open winner.

But the 25-year-old Ostapenko was always in control to ensure that Gauff must wait at least a bit longer for a first major title.

Gauff told reporters it was a “little bit frustrating”, then her voice suddenly began to crack, the tears flowed and the teenager was offered a tissue.

“I’m OK, we can keep going,” she said.

- ‘Super excited’ -

The men’s draw has also seen a series of surprise results. Unseeded Jiri Lehecka added to the list by beating sixth-seeded Felix Auger-Aliassime.

The 21-year-old Czech was knocked out in the first round at the four majors last year but was too hot for the Canadian, winning 4-6, 6-3, 7-6 (⁷⁄₂), 7-6 (⁷⁄₃).

“After losing in the first round last year, if someone had told me before the tournament that I would be playing like this, I wouldn’t have believed them,” said 71st-ranked Lehecka.

“I’m super happy and excited.”

Karen Khachanov also reached the last eight after the Russian 18th seed blew away Japan’s Yoshihito Nishioka 6-0, 6-0, 7-6 (⁷⁄₄).

The men’s draw has an unfamiliar look to it.

Injury-hampered top seed and defending champion Rafael Nadal went out in round two, as did second seed Casper Ruud.

Also out early was the 2021 and 2022 runner-up Daniil Medvedev.

But nine-time Melbourne champion Novak Djokovic is still on the scene as he chases a record-equalling 22nd Slam title.

The fourth seed from Serbia is however nursing a hamstring injury.

Stefanos Tsitsipas is now the highest-ranking seed left in the decimated men’s draw at three.

The Greek faces young Italian Jannik Sinner, seeded 15, later Sunday.