Laura Robson produced the performance of a lifetime to knock out number eight seed Petra Kvitova 2-6 6-3 11-9 and advance to the third round of the Australian Open.
The British number two kept her cool to seal a match that went into the early hours of the morning, and will now move on to face 29th seed Sloane Stephens in the next round.
Early nerves appeared to get the better of the Brit in her opening service game of the match, hitting two double faults as Kvitova broke to love. But the 18-year-old immediately restored parity in the next before holding her serve at the second attempt.
Both women were struggling to find their rhythm with the ball in hand, but Kvitova was making the most of her opportunities and broke Robson twice more to open up a 5-2 lead.
The Brit was not as clinical and spurned five opportunities to break in the deciding game and the Czech sealed the opening set with a fierce ace.
The tables turned in the second as Robson began targeting Kvitova's forehand. She got her reward in the third game, forcing a costly error for her opponent to seize the advantage.
The Olympic silver-medalist was growing in confidence and a wild shot from the world number eight gifted her a second break and two games to serve out the set.
Robson spurned the first opportunity, but did not pass up the second attempt and levelled the match after a forehand from Kvitova went wide.
The Czech started brightly in what would be a thrilling third set. The 2011 Wimbledon champion broke Robson early but then brought the Brit back into the game with consecutive double faults in game five.
Both players were becoming wasteful with the serve once again but Robson took advantage in the 11th game and had the opportunity to close out the match.
Kvitova hit back with a superb array of shots to deny Robson but was powerless to stop a blistering forehand which broke her in the 19th game which put the Brit on the brink of victory once more.
And the Brit held her nerve to complete the biggest victory of her career as she confidently served out to love.