Thai qualifier Luksika Kumkhum has added to the destruction of the Australian Open women's draw to join teenage prodigy Marta Kostyuk among three qualifiers through to the third round.

Kumkhum, the world No.124, sent Swiss ace Belinda Bencic crashing out with a 6-1 6-3 thumping on Wednesday to assume pole position at the top of a bottom half of the draw blown wide open.

The 521st-ranked 15-year-old Kostyuk then took out Australian wildcard Olivia Rogowska 6-3 7-5 to become the youngest player since three-time champion Martina Hingis in 1996 to make the last 32 at Melbourne Park.

As the reigning Open junior champion, Kostyuk's second-round victory over Rogowska was no great surprise.

But Kumkum's over Bencic, two days after the former world No.7's shock opening-round triumph over seven-time major winner Venus Williams, certainly was.

The Asian will play Petra Martic in the round of 32 after the Croatian saw off the challenge of Romania's Irina-Camelia Begu 6-4 7-6 (7-3).

The winner will fancy their chances of going even further after Julia Goerge's surprise removal from the top quarter.

The German 12th seed had her 15-match, four-month winning streak abruptly halted in a 6-4 6-3 loss to Frenchwoman Alize Cornet.

Kumkhum's commanding victory over Bencic marked the second time the 24-year-old had caused a significant boilover at Melbourne Park.

Four years ago she dispatched Czech Petra Kvitova in the opening round.

In other women's action on Wednesday, No.4 seed Elina Svitolina set up an all-Ukrainian clash against Kostyuk by beating Czech Katerina Siniakova 4-6 6-2 6-1.

Kateryna Bondarenko continued a banner day for the Ukrainian contingent with a 6-2 6-3 rout of Russian 15th seed Anastasia Pavlyuchenkova.

Bondarenko will next play No.19 seed Magdalena Rybarikova after the Slovakian overcame a second-set blip to beat Belgian Kirsten Flipkens 6-4 0-6 6-2.

Czech Denisa Allertova continued her dream run with a 6-4 7-6 (7-5) defeat of former semi-finalist Zhang Shuai and will play fancy her chances of going even further on Friday.

Allertova will take on Magna Linette after the Pole removed Russian 22nd seed Daria Kasatkina from the draw with a 7-6 (7-4) 6-2 upset victory.

In the bottom quarter, second seed Caroline Wozniacki survived a huge scare, saving two match points and recovering from 5-1 down in the deciding set to deny lowly ranked Croat Jana Fett 3-6 6-2 7-5.

Wozniacki plays Dutchwoman Kiki Bertens next and could face French Open champion Jelena Ostapenko for a semi-final berth after the Latvian eked out a tough 6-3 3-6 6-4 win over China's Ying-Ying Duan.

Seventh-seeded Ostapenko will face Anett Kontaveit in a Baltic derby after the Estonian took out German Mona Barthel 6-3 4-6 6-3.