Title favourite Elina Svitolina has survived a stern test against rising Czech Katerina Siniakova to reach the third round of the Australian Open at Melbourne Park.

Fourth-seeded Svitolina had to battle back from a set down to beat Siniakova 4-6 6-2 6-1 and set up a showdown on Friday with 15-year-old Ukrainian qualifier Marta Kostyuk.

Kostyuk earlier on Wednesday ousted Australian wildcard Olivia Rogowska 6-3 7-5 to become the youngest player since Martina Hingis 21 years ago to make the last 32 in Melbourne.