Coco Gauff survives strong challenge from Marta Kostyuk to move into Australian Open last four… as potential rematch with Aryna Sabalenka awaits

Coco Gauff recovered from a nightmarish start and a midmatch wobble against Marta Kostyuk to move into the Australian Open semifinals, beating the Ukrainian 7-6 (8-6), 6-7 (7-3), 6-2 to set up a potential rematch vs. Aryna Sabalenka.

The American found herself down 5-1 in the first set of the quarters and staring down a must-win second, but won five of the next six games to claw herself back and seize control of the match, which she ultimately won after three hours and eight minutes.

Gauff, who committed 24 unforced errors in the first set, built a 6-5 lead with the chance to serve for the set after breaking Kostyuk for a third time.

But Kostyuk answered with a break of her own to force a tiebreak, which Gauff ultimately won after the Ukrainian took a medical timeout for an ailing foot.

The 19-year-old saved a set point at 6-5 in the tiebreak, and also survived a set point when Kostyuk was leading 5-3.

Marta Kostyuk got off to a hot start but ultimately could not hold off the No. 4 seed Gauff

Kostyuk began the second set by breaking Gauff but the American returned the favor twice more and built a 4-2 lead going into her serve.

From there, though, neither player could defend their serve over the next three games. 

Kostyuk managed another break down 4-2 to stay in the match, but couldn’t hold serve in a chaotic eighth game of the set that featured a 21-shot rally and three deuces.

But Gauff could not capitalize on her chance to serve for the match up 5-3, and Kostyuk ultimately held serve over her next two opportunities to set up a second tiebreak of the match.

Coco Gauff battled in Melbourne for over three hours to move into the semifinals

Kostyuk tested the 19-year-old American but lost steam in the third and final set

Gauff will face 2023 US Open finalist Aryna Sabalenka if the Belarusian wins her next match

This time, it was the underdog who came out on top after winning the first four points, one of which was an outrageous 36-shot rally that ended with Gauff hitting wide of the line with a forehand.

The American would regain her momentum in the final set as she raced out to a 5-0 lead, with a frustrated Kostyuk slamming her racket in the third game and ultimately failing to recover despite winning a couple of late consolation games.

Gauff, the No. 4 seed, will play the winner of the quarterfinal match between  Sabalenka and Barbora Krejcikova.

Gauff defeated Sabalenka in the US Open final last summer to capture her first Grand Slam.