MELBOURNE, Australia — Already down a set and facing a break point against Iga Swiatek, No. 50-ranked Linda Noskova decided she had nothing to lose.

She won 11 of the next 12 points to take the second set and swing momentum in their third-round match Saturday, ultimately becoming the first teenager to beat a No. 1-ranked woman at the Australian Open since 1999.

With a big serve and equally big groundstrokes, she unsettled Swiatek and held her cool, even under pressure in the last game to serve it out, for a 3-6, 6-3, 6-4 victory that means there’s no top 10 players in the top half of the draw.

“I’m just really kind of exhausted mentally and physically,” Noskova said in her post-match news conference following the upset. “I just believed my game tonight. I just really wanted this.”

Swiatek is a four-time major winner but has never been past the semifinals at Melbourne Park. Even so, she was on an 18-match winning streak and expected to account for the 19-year-old Noskova, who is making her main draw debut at the tournament.

Swiatek beat 2020 Australian Open champion Sofia Kenin in the first round and had to rally from 4-1 down in the third to overcome 2022 finalist Danielle Collins in the second.

But after taking the first set against her Czech opponent, she struggled for rhythm. The decisive break was in the seventh game of the third set, with two forehand errors costing Swiatek the game.

Two games later, she held at love and forced her rival serve it out, then jumped to 0-30 lead in the 10th game.

But Noskova won the the next four points to finish it off quickly, including an ace to set up match point. She’ll next play Wimbledon semifinalist Elina Svitolina.

Swiatek said the tough opening matches didn’t hurt her.

“Physically I felt — honestly, I didn’t feel anything. So pretty good,” she said. “Mentally, as well, I felt like actually I came back in my match against Danielle, and I could kind of start over and not expect a lot, just try to play my game.

“I felt like I had everything under control until she broke me in the second set,” the 22-year-old Pole added. “Sometimes, yeah, I was rushing it. I just wasn’t playing kind of with my intuition and naturally.”

Swiatek’s loss leaves No. 12 Zheng Qinwen as the highest-ranked player and two-time Australian Open winner Victoria Azarenka as the only past major winner in the top half of the draw.