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.


Leclerc laps fastest for Ferrari in first US GP practice
Bayern coach Kompany hospitalised after collapsing during training session
Alexander Volkanovski's title defence headlines UFC 333 in Abu Dhabi
Juventus fight back to draw with Rennes as Leverkusen go top
South Africa level test series with big win over Australia
