Qualifier Katie Volynets caused an upset on Thursday when she ousted world No.9 Veronika Kudermetova 6-4, 2-6, 6-2 to become the first American qualifier to reach the Australian Open women’s singles third round in 30 years.

Volynets, 21, ranked 113 in the world, wobbled in the second set as Kudermetova levelled the match, but threw everything at her opponent in the decider.

“I literally have the chills because the fans here are just incredible,” Volnyets said afterwards.

“I’ve never played in a stadium this packed and with that many people keeping the energy up for me. It was awesome.”

She will next meet either China’s Zhang Shuai or Croatian Petra Martic for a place in the fourth round.

Earlier, Aryna Sabalenka beat American Shelby Rogers 6-3, 6-1, but another American, Taylor Townsend, was beaten by 19th seed Ekaterina Alexandrova 1-6, 6-2, 6-3.