Spain's Paula Badosa reached her first Grand Slam semifinal after a straight-set upset of third seed Coco Gauff at the Australian Open on Tuesday.

The 11th seed stunned Gauff 7-5, 6-4 in one hour and 43 minutes in hot and sunny conditions on Rod Laver Arena in Melbourne.

Paula Badosa hits a return during the women's singles quarterfinals match between Coco Gauff of the United States and Paula Badosa of Spain at the Australian Open tennis tournament in Melbourne, Australia, Jan. 21, 2025. (Photo by Chu Chen/Xinhua)

The 27-year-old Badosa will play defending champion Aryna Sabalenka or 27th seed Anastasia Pavlyuchenkova in the semifinals.

"I'm a bit emotional and, overcoming something like this [getting past the quarterfinals] today. I wanted to play my best game and I think I did it," said Badosa, who beat a top-10 player in a Grand Slam for the first time.

"I'm super proud of my level today," she said.

Former US Open champion Gauff entered as the favorite having ridden a surge of momentum into the last eight with 13 straight wins since clinching the season-ending WTA Finals last November.

But she had no answers for fired-up former world No. 2 Badosa, who is determined to turn around a modest record in Grand Slams.

Badosa has been in aggressive form in Melbourne having started her campaign by defeating China's Wang Xinyu in straight sets.

She had lost both matches to Gauff last year in three sets, but was undaunted by the challenge and attacked on her backhand side to earn two early break points.

Gauff, however, lifted her intensity to hold and was dominant on serve until the 11th game when Badosa earned a break point after finishing off a spectacular rally with a crisp volley.

Badosa broke serve before wrapping up the first set and pumping her fist in steely celebration.

Gauff was under a barrage from Badosa early in the second set, and she fended off four break points before cracking when her looping forehand sailed over the baseline.

But Gauff capitalized on a loose service game from Badosa to draw level at 2-2.

Her fightback was short-lived as Badosa rediscovered her precision and hit the lines to twice break a dispirited Gauff.

Badosa failed to close it out on serve in the eighth game, but there was no late twist as she sank to her knees in emotional celebration.