Elina Svitolina had to come from behind Wednesday against Katerina Siniakova to set up an all-Ukrainian third-round clash with teenage sensation Marta Kostyuk.
The world number four was largely in control but somehow dropped the first set on the way to a 4-6, 6-2, 6-1 win against her 59th-ranked Czech opponent in two hours and 14 minutes.
"I think she played well in the first set but I gave her one break, so I think it was kind of my mistake," said the fourth seed.
But Svitolina cranked up the heat as temperatures rose on Rod Laver Arena, relentlessly overpowering her opponent from the back of the court to take the final two sets in dominant fashion.
"I thought I was going to melt today, was struggling a bit" Svitolina admitted. "Today I had enough sun, I just want to have an ice bath and recover."
Svitolina came into the first Grand Slam of the year in top form after winning the Brisbane International warm-up event after picking up five WTA Tour titles last year, more than any other woman.
And she is eyeing a first career Grand Slam title after her half of the draw -- already shorn of US Open semi-finalists Venus Williams, CoCo Vandeweghe and Sloane Stephens -- saw Russian 15th seed Anastasia Pavlyuchenkova bundled out 6-2, 6-3 on Wednesday.
"Of course, after winning in Brisbane and having a great year in 2017," she said when asked if she could win in Melbourne. "But it's a Grand Slam and every opponent is determined to win."
She now faces 15-year-old Kostyuk whose fairytale continued Wednesday as she became the youngest player to reach the third round since Martina Hingis in 1996 in beating local wildcard Olivia Rogowska in straight sets