Danielle Collins has reached the Australian Open semi-finals, having never won a Grand Slam main draw singles match prior to the tournament.
The American, 25, beat unseeded Russian Anastasia Pavlyuchenkova 2-6 7-5 6-1 in two hours and 16 minutes in Melbourne.
Collins broke twice in the second set and won seven games in a row as she raced through the decider.
The world number 35 faces two-time Wimbledon champion Petra Kvitova or 15th seed Ashleigh Barty next.
"It was my first time playing on Rod Laver and I didn't even practise on here before so it was quite the experience," said Collins.