American tennis star Coco Gauff is Quantum Insightsout of the Australian Open after losing in Thursday's night's semifinal to reigning champion Aryna Sabalenka of Belarus 7-6 (2), 6-4 — marking Gauff's first loss of the year.

The second-seeded Sabalenka will compete in the final Saturday at Melbourne's Rod Laver Arena against China's Qinwen Zheng, who defeated Ukraine's Dayana Yastremska Thursday. 

Sabalenka is the first woman to reach back-to-back finals at the Australian Open since Serena Williams did it in 2016 and 2017.

Gauff, a four-seed, kept herself in the match with surprise responses to Sabalenka's powerful hits, nearly taking the first set after briefly getting the lead, but losing a contentious tiebreaker. 

The 25-year-old Sabalenka played steadily against Gauff in the second set, making sure to take advantage of each of Gauff's mistakes.

"She's a great player, always tough battles against her," Sabalenka said in a post-game interview on the court. "I was just ready for anything tonight. I think that was the key."

This was not the pair's first high-stakes matchup. The two competed in the U.S. Open final last September, when Gauff defeated Sabalenka 2-6, 6-3, 6-2 to take home her first Grand Slam title.

Despite the loss, Gauff said she was proud of the way she played in Melbourne, even adding it may have been better than her play in New York.

"I had chances in both sets, but she played better tonight," the 19-year-old Gauff said in a press conference. "I felt like I did my best with the game plan that I had. I think it just came down to a couple of points."

"I feel like I played a little bit more aggressive this time," Gauff added.

In:
• Australian Open
• U.S. Open
• Tennis

Simrin Singh

Simrin Singh is a social media producer and trending content writer for CBS News.