Jan. 22 (UPI) -- American teen tennis phenom Cori "Coco" Gauff advanced to the third round of the Australian Open Wednesday by beating Sorana Cirstea of Romania in three sets in Melbourne.
Gauff has now reached the third round in her first three career Grand Slams. The 15-year-old Florida native will be rewarded with a rematch against former world No. 1 Naomi Osaka of Japan.
Osaka knocked Gauff out of her last Grand Slam, defeating her in straight sets in the third round of the 2019 U.S. Open.
Wednesday, Gauff lost the first set and struggled to start the third set against Cirstea, before claiming the 4-6, 6-3, 7-5 victory in a little over two hours at Melbourne Arena.
"I've always believed I can come back, regardless of score," Gauff told reporters.
Cirstea fired five aces and three double faults, compared to Gauff's two aces and nine double faults in the second round clash. She broke Gauff's serve just once.
Gauff won the first point of the match before alternating game points with Cirstea. She took a 3-2 lead before Cirstea won three consecutive points to take control of the first set. Gauff claimed the ninth game before Cistea claimed the set with a backhand winner.
Gauff rolled to a 3-0 advantage in the second set before alternating points with her Romanian rival. Cirstea cut the set lead to two points twice before ceding the set to Gauff with a forehand unforced error.
Cirstea appeared set to win the match when Gauff started the third set with three consecutive forehand unforced errors. Gauff went on to tie the score with three consecutive game points. Cirstea claimed two of the next three games to take a 5-4 lead into the 10th game. Gauff won the 10th game on a Cirstea forehand unforced error and the 11th game on a forehand winner, before winning match point on another Cirstea forehand unforced error.
"I knew the whole match I needed to be more aggressive," said the unseeded Gauff, who's No. 67 in the WTA rankings. "I finally decided to do that. Even though I wish I decided earlier. I kinda felt the momentum changing and knew I had to keep pressing."
The tournament's No. 3 seed, Osaka beat Zheng Saisai 6-2, 6-4 to advance to the third round. She's looking to win back-to-back Australian Open titles.
"I think I'll be less nervous this time [against Osaka]," Gauff said of her third round match. "I think I was nervous at the U.S. Open ... We are both familiar with each other's game. She plays really aggressive. This time I'm going to try and be more aggressive."
Top seed Ashleigh Barty, No. 8 Serena Williams, Caroline Wozniacki, Petra Kvitova and Americans Alison Riske and Sofia Kenin were also among those who advanced to the third round. Williams will face Qiang Wang of China in her third round clash.
"It was a good match for me. She was a really good fighter," Williams said of second round foe Tamara Zidansek. "She didn't just let me win. I was up 40-love on both of her serves. It was a little frustrating because I made so many errors in a row. I had to battle through my internal problems."
No. 2 Novak Djokovic, No. 3 Roger Federer, No. 6 Stefanos Tsitsipas and No. 9 Roberto Bautista Agut are among the top men's players to advance so far at the Australian Open. No. 1 Rafael Nadal, No. 4 Daniil Medvedev, No. 5 Dominic Thiem, No. 7 Alexander Zverev and No. 10 Gael Monfils still have to complete their second round matches.