Fifteen-year-old Coco Gauff has set up a thrilling clash with defending champion Naomi Osaka in Melbourne.
She saw off Romania's Sorana Cirstea 4-6, 6-3, 7-5 in two hours and six minutes.
"It's amazing," said Gauff. "Honestly, I didn't think I would get so much support in Australia. I was down 3-0 and you really made me believe."
Despite an angry outburst, Osaka defeated Saisai Zheng 6-2, 6-4 in one-hour-and-20 minutes.
"I just wanted to fight," said Osaka, adding, "I've been in this position before on this court and I was thinking that I really don't want to play the third set this time."

Meanwhile, world number one Ashleigh Barty also progressed into the third round with 6-1, 6-4 victory over Slovenia's Polona Hercog.
Caroline Wozniacki also progressed with 7-5, 7-5 victory over Ukrainian 23rd seed Dayana Yastremska.


Mexico bounce Czechs out of World Cup with win
South Africa beat South Korea to reach World Cup knockout stage for first time
Qatar’s Assim Madibo gets 5-game ban for injuring Canada's Ismael Kone
Morocco earn comeback win over Haiti to reach last 32 as group runners-up
Vinicius fires Brazil into World Cup knockouts with win over Scotland
