Marta Kostyuk became the youngest player to reach the third round of a Grand Slam since 1997 as the 15-year-old qualifier beat Olivia Rogowska at the Australian Open.
The world number 521 won 6-3 7-5 and plays fourth seed and fellow Ukranian Elina Svitolina in the last 32.
Kostyuk is the youngest player to reach that stage at a Slam since Mirjana Lucic-Baroni in the 1997 US Open.
She is the youngest in the last 32 at Melbourne since Martina Hingis in 1996.
Kostyuk, the 2017 Australian Open girls champion, said: "I felt so bad on the court - it was hot - but I made it through.