The two biggest upsets of this year's Australian Open occurred Thursday with the two finalists at 2021 WTA Finals falling. Clara Tauson of Denmark took out No.6 seed Anett Kontaveit, and France's Alizé Cornet eliminated No.3 seed Garbiñe Muguruza.

Another upset by Alizé: The World No.61 Cornet, playing in her 63rd Grand Slam tournament and 17th Australian Open, breezed past 2020 Australian Open runner-up Muguruza 6-3, 6-3 to reach the third round in Melbourne for the sixth time in her career.

It is the 10th win over a Top 5 player for former No.11 Cornet, and her first since she beat then-No.4 Sofia Kenin at the Western & Southern Open a year and a half ago.

It also continues a pattern of success for Cornet, 31, against Muguruza. The Frenchwoman took a 3-2 lead in their head-to-head. Cornet lost their first two meetings but has now won their past three, including last year on the grass in Berlin.

Cornet speaks: "It was a very good match, very right tactically from the beginning till the end," Cornet said afterward. "It's been awhile [since I] beat a Top 5 player in a slam, so it's a really good feeling. 

"I really enjoyed it today, which doesn't mean I will enjoy it tomorrow! That's why when the fun is here, you have to take it. You never know how you're going to apprehend, feel the next match."

Stat corner: Thursday's match in Melbourne was a pristine display by Cornet, who never faced a break point in the 87-minute affair. Cornet won 83 percent of her first-service points to ease through her deliveries.

By contrast, reigning Akron WTA Finals champion Muguruza was unglued by miscues. Cornet and Muguruza had a matching winner total, with 17 apiece, but Cornet had only 16 unforced errors while Muguruza more than doubled that total with 33.

Match moments: Cornet got off to a flying start, holding 0-40 leads in each of Muguruza's first two service games. Muguruza was able to wriggle out of the second instance to hold, but she was still down a break as Cornet carved her way to the lead.

Cornet, who had already collected three Top 10 wins at Grand Slam events in her career, remained unbothered as Muguruza saved two set points at 5-2. Cornet calmly served out the opening frame in the next game to grab the one-set advantage. 

At 2-2 in the second set, Cornet fired a wicked passing shot winner to earn the first break of the second set, and that would be all she needed. Cornet broke Muguruza at love in the final game of the match for good measure, closing out the upset.

Next up: Cornet will square off against No.29 seed Tamara Zidansek of Slovenia in the third round. It will be their first meeting.

Zidansek, a 2021 Roland Garros semifinalist, defeated Heather Watson of Great Britain 7-6(4), 6-4 on Thursday. It was Zidansek's second win this month over Watson; she also beat the Brit in the first round at Adelaide last week.

Tauson upended Kontaveit 6-2, 6-4 to reach the third round of a Grand Slam event for the first time in her career.

Read more: Getting to know Clara Tauson

Fast facts: The rising 19-year-old, currently ranked at a career-high No.39, needed 1 hour and 19 minutes for her first Top 10 win, in only her second match against Top 10 opposition. 

The former No.1 junior Tauson continues her rise into the upper echelon of the women's game. The Dane started 2021 outside the Top 100 but picked up her first two WTA singles titles last year, in Lyon and Luxembourg.

For the 2020 Australian Open quarterfinalist Kontaveit, the loss quells her own incredible rise, where she won 28 of her past 32 matches in 2021 to crack the Top 10. 

Words from the winner: "I think everything was working," Tauson said with a smile in her post-match press conference. "I felt really comfortable on court. It was a nice court to play on. The weather was really good today. I just felt really good out there. Just went for everything and it worked today. 

"It's the first time I'm in the third round of a Slam. Playing a player like her to reach it, it's a really big achievement for me. Obviously it was one of the things I really wanted to do, to beat the good players in the bigger tournaments.

"Doing it in a Slam is a really great feeling. It's just a lot of hard work that I've put into it. That it's here already in one of the first tournaments of the year is a really nice feeling. But I still have some work to do. I cannot be too happy with the win today, but I am really happy."

By the numbers: In a bruising battle between two powerful players, it was Tauson who played the much tidier match. She fired 20 winners to 13 unforced errors, while Kontaveit's 15 winners were undone by 27 unforced errors.

Tauson was particularly adept on return, winning over half of Kontaveit's service points, including 63 percent when facing the Estonian's second service.

Key plays: Tauson controlled the opening set from start to finish. The Dane broke Kontaveit in the first game of the match, then used heavy service returns to break the seeded star easily for a 5-2 lead. A backhand winner by Tauson closed out a love hold to seal the set.

Kontaveit crept closer in the second set as the pair twice exchanged breaks to reach 4-4. But there, Tauson converted her third break point of that game after a wide forehand by Kontaveit, moving ahead by a break for the third time in the set.

Serving for the match, Tauson showed no nerves as she quickly reached triple-match point. A final forehand miscue by Kontaveit ended the match, and Tauson had earned her career-best win by ranking.

Next up for the Dane: Tauson will continue to be tested as she will meet No.27 seed Danielle Collins of the United States in the third round. Collins beat Ana Konjuh of Croatia 6-4, 6-3 in the second round.

Collins' breakthrough Grand Slam run came at the 2019 Australian Open, where she reached the semifinals.