Just one day shy of her 16th birthday, Ukrainian Marta Kostyuk fought back from the brink twice to defeat American Kristie Ahn 6-7 (1), 6-3, 9-7 and reach the final round of Wimbledon qualifying on Wednesday.

Ahn served for the match twice but Kostyuk refused to fold as she stepped closer to making her Wimbledon main draw debut with a hard-fought two-hour 42-minute triumph, which she celebrated with a signature acrobatic backward flip on court.

Kostyuk, who made a surprise run to the third round of the Australian Open last January to become the youngest woman to make that stage in Melbourne since Martina Hingis in 1996 next faces Spaniard Sara Sorribes Tormo on Thursday.

“I was just so happy that I went through this second round because last year I was losing straight in Roland Garros, Wimbledon and US Open, so I was like this one I have to win. I feel like I’ve broken the wall,” Kostyuk said after the match.

“I was so pissed the whole match, I have no idea why. I was just tired probably.”