Australian Open Day 6: Daniil Medvedev dominates, Andrey Rublev falls

Villain one day, hero the next. Daniil Medvedev won over the Australian Open crowd with his convincing win over Botic van de Zandschulp.

Medvedev dominated during the performance, taking three straight sets (6-4, 6-4, 6-2) from van de Zandschulp. It was the first time the two played since Medvedev defeated van de Zandschulp at the US Open. Medvedev went on to win that event.

Medvedev's serves got the best of van de Zandschulp on Day 6. Medvedev registered 10 aces to van de Zandschulp's three aces. The two managed to both hit 209 kmh with their fastest serves of the match, but Medvedec consistently hit higher speeds on both his first and second serves.

With the win, Medvedev advanced to the fourth round of the Australian Open. He'll take on American Maxime Cressy on Tuesday.

Daniil Medvedev wins Australian Open fans over

Medvedev — the No. 2 seed — managed to do something completely unexpected during the win. As he dominated van de Zacndschulp, Medvedev heard cheers from the fans. This was a major change from Thursday, when Medvedev called the fans "low IQ" for booing him during his Round 2 match against Australian Nick Kyrgios.

Medvedev had fun with the fans after his Day 6 win, saying, "Every relationship has its ups and downs."

Medvedev also joked that the Australian fans are much nicer when he's not beating an Australian player in their home country.

Andrey Rublev upset by Marin Cilic in third round

Marin Cilic is no stranger to reaching Round 4 of the Australian Open. Even with No. 5 seed Andrey Rublev standing in the way, Cilic pulled off an upset to make it to the Round of 16 at the Australian Open for the eighth time in his career.

The games were tight early. Cilic pulled off narrow wins in the first two sets, 7-5, 7-6. Rublev recovered to take the third set 6-3. Rublev's rally didn't last much longer. After trading the first two games in the final set, Cilic charged ahead, going up 4-1 on Rublev. Cilic eventually won the fourth set, and the match, 6-3.

He was fired up about the win.

With the win, Cilic will take on Felix Auger-Aliassime in the fourth round.

Aryna Sabalenka, Stefanos Tsitsipas advance to fourth round

Rublev represented the biggest upset of Day 6. Other top seeds, including Aryna Sabalenka and Stefanos Tsitsipas, advanced to the fourth round of the tournament with wins Saturday.

For a moment, it looked like Sabalenka was in trouble. She dropped the first set to Marketa Vondrousova 6-4, but then rallied to take the next two sets and the match 6-3, 6-1. Sabalenka was at her best in the final set. After Vondrousova took the first game, Sabalenka won the next six to take the match.

Tsitsipas needed four sets to dispatch Benoit Paire to make it to the fourth round. Tsitsipas got off to a strong start early, taking the first two sets from Paire 6-3, 7-5. Paire refused to go down without a fight. He took the third set 7-6. Paire fought hard in the final set, but couldn't recover after two double faults in the 10th game. Tsitsipas took that set 6-4, winning the match. He'll take on American Taylor Fritz in the fourth round.

Anastasia Pavlyuchenkova falls to Sorana Cirstea

The other major upset involved No. 10 seed Anastasia Pavlyuchenkova. She was defeated by Sorana Cirstea in three sets (6-3, 6-2, 6-2) Saturday. Pavlyuchenkova's made 31 unforced errors during the match, which proved to be the difference.

There were no other major upsets in Day 6. Felix Auger-Aliassime, Simona Halep, Jannik Sinner and Iga Swiatek all advanced to the fourth round with their performances Saturday.