MELBOURNE, Australia — Marta Kostyuk, a 15-year-old qualifier from Ukraine who beat 25th-seeded Peng Shuai in the first round, has advanced to the third with a 6-3, 7-5 win over Olivia Rogowska, a wild-card entry from Australia.
Kostyuk, who entered the tournament ranked No. 521, had already played six hours on court through three three-set qualifying rounds before beating Peng in the first round.
The win over Peng gave Kostyuk the distinction of being the youngest player to win a main-draw match at the Australian Open since Martina Hingis in 1996.
Kostyuk, a former Australian Open junior champion, will play either fourth-seeded Elina Svitolina or Katerina Siniakova in the third round.
Her fellow Ukrainian Kateryna Bondarenko beat No. 15-seeded Anastasia Pavlyuchenkova, a quarterfinalist here last year, 6-2, 6-3, to reach the third round in Australia for the third time.
The 31-year-old Bondarenko broke Pavlyuchenkova's serve four times and only dropped her own serve once to register her 20th career win against a Top 20 player.