15-year-old Coco Gauff caused another major upset of the day in the women’s singles event of the ongoing Australian Open as she defeated defending champion Naomi Osaka at the Rod Laver Arena on Friday.

The American, who is making her Australian Open debut as an unseeded player, won the third-round match 6-3, 6-4 to take sweet revenge of her last year’s US Open-defeat against Osaka to extend their budding rivalry which many expect to light up the women’s game in the ongoing decade.

The youngest player in the singles draw Gauff, who trained with Serena Williams in the off-season, had said that she would be more aggressive against Osaka after her loss at the US Open.

Gauff won the first set in 32 minutes after Osaka dropped her serve in the eighth game and committed more unforced errors. The teenager continued the dominance in the next set as well as she served for the match at 5-4.

Osaka hit five aces to Gauff’s 1, but it was the latter’s higher win percentage of 76 on 1st serve that set the tone of the game. In total Gauff won 60 points, while Osaka fell way behind with 45.

“I was just telling myself one point at a time and just keep fighting because you never know what happens on this court,” Gauff said after her win over Osaka.

Earlier on the day, Serena, who was bidding to win her 24th Grand Slam title, suffered a shock exit after losing her third-round match 6-4, 6-7 (2), 7-5 to Wang Qiang of China at the Rod Laver Arena.

The world number eight lost her opening set before rallying to equal the match in the second. However, the 27th seeded Wang resisted Serena in the final set to cause the first major upset in this year’s first Major.

On the other hand, former world number one and a tearful Caroline Wozniacki bid adieu to Tennis after losing to Ons Jabeur. Wozniacki, who had announced her retirement from Tennis after this year’s Australian Open, lost 7-5, 3-6, 7-5.