Laura Robson produced a stiring fightback to defeat world No.8 Petra Kvitova in a three-hour marathon and book a place in her first-ever Australia Open third round in Melbourne.
The British No.2 began nervously, losing the first set 6-2 as Kvitova showed glimpses of the form that that took her to the 2011 Wimbledon title.
Robson bounced back to claim the second 6-3 after claiming four games in a row as Kvitova continued to produce multiple serving errors.
Kvitova won the opening three games of the deciding third set to put her in pole position for the third round, but Robson turned it around, breaking in the 11th game to serve for the match.
However, consecutive forehand errors saw Robson miss the chance to claim victory a first time but she eventually prevailed 11-9 in the the tie-break.
"I knew it was going to be tough and I always struggle to play lefties so trying to return her serve was very, very hard so as soon as I had my return and had more confidence I managed to get myself back in the match," Robson said.
Both players began riddled with nerves on Rod Laver Court, with the pair broken in their opening service games with numerous double faults undermining their challenge. Kvitova did take the initiative in the fifth game to lead 4-2 after holding serve as Robson failed to find a foothold in the contest.
The Czech seed was eventually able to serve out the set but not before Robson scuppered six break point chances in game seven, until Kvitova found her range to take her third set point.
If the first set that had passed the British No.2 by then Robson set out to make amends in the second, wining four consecutive games to lead 5-1.
Kvitova did break back but Robson discovered more consistency on her serve, winning 80% of points upon making a first serve to take the second set 6-3 to level the match.
However the deciding third set began with the 2011 Wimbledon champion finally finding her feet, taking the opening three games as Robson suffered more problems on her second serve to leave the Briton on the brink of elimination.
But the Olympic mixed-doubles silver medallist came again, holding serve for the first time before taking advantage of Kvitova missing a game point and then finding the tram lines as Robson's footwork sought improvement.
Consecutive breaks of serve worked to define the inconsistent nature of the contest as Robson creamed a forehand down the line to bring up more break points for the Brit.
The three consecutive breaks were brought to a halt by a shaky Robson service game to level the set at 4-4, but it proved to be an important blow as she set up a break point from 30-0 down on the Kvitova serve.
Back-to-back aces hauled Kvitova out of her predicament and despite relentless pressure from Robson, she held to pile the pressure back on the world No. 53.
The 18 year old produced a reaction far beyond her years, levelling at 5-5 before forcing a break chance which Kvitova plundered long to allow Robson to serve out the match an opportunity she missed with two wayward forehands.
But she eventually produced the required consistency to take the tie-break 11-9 to book a place in her first ever Australian Open third round where she will face American Sloane Stephens.