Paula Badosa has reached her first-ever Grand Slam semifinal…

The 27-year-old Spanish tennis player, the tournament’s No. 11 seed, upset No. 3 seed Coco Gauff in the quarterfinals of the Australian Open on Tuesday to advance to the next round.

Gauff’s forehand and serve abandoned her at the worst time at Melbourne Park in the unexpected loss.

Gauff had entered the match at Rod Laver Arena with a 9-0 record in 2025 and was on a 13-match winning streak that dated to her title at the WTA Finals in November.

Using tweaks to some key strokes to great effect in the hopes of earning a second Grand Slam title at age 20, the 2023 US Open champion had dropped only one set through four matches at Melbourne Park this year.

“She’s full of confidence. But I’m playing well, too,” Badosa said ahead of the contest. “I’m ready to face her.”

Was she ever.

Badosa now heads to her first Grand Slam semifinal

Gauff finished with 41 unforced errors, a total that included six double-faults – one of them on the last point of the game that put Badosa ahead 5-2 in the second set – and 28 missed forehands.

She didn’t earn a break point until after she trailed by a set and a break in the second.

Badosa reached a career-best ranking of No. 2 in 2022, but then dealt with a serious back injury that had her contemplating ending her tennis career.

“I would never think that, a year after, I would be here,” Badosa said. “I’ve been through a lot. In the past, I was one of the best players in the world.”

She’ll next face No. 1 Aryna Sabalenka, the two-time defending champion in Melbourne, or No. 27 Anastasia Pavlyuchenkova, the runner-up at the 2021 French Open. Their quarterfinal was to be played Tuesday night.