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By Ian Ransom
MELBOURNE Jan 13 (Reuters) - Thai world number 88 Luksika Kumkhum sprang the biggest upset of the Australian Open's first day by dumping sixth seed and former Wimbledon champion Petra Kvitova 6-2 1-6 6-4 on Monday in her first match against a top 10 player.
The 20-year-old Luksika, the only Thai in the top 200 of the women's tour, showed great composure at a frenetic Margaret Court Arena to fend off the powerful Czech who came roaring back into the first round clash to force a decider.
With the contest in the balance at 3-3 in the third, Kvitova squandered a chance to break serve with a fluffed backhand and double-faulted in the next game to hand the Thai a chance to serve out the match.
Luksika, who made her grand slam debut at Melbourne Park last year as a teenaged qualifier, endured her own wobble on serve to hand the break back, but then went for broke as Kvitova served to stay in the match.
The pressure told on the imposing Czech, who sprayed a forehand to concede two match points and pushed another wide to hand the Thai the biggest win of her career.
Wearing a grin that displayed a mouthful of braces, Luksika bowed to a crowd that had been firmly behind the underdog and struggled to convey her emotions in halting English.
"I just tried like (there was) nothing to lose, just play the best today," the short-haired Thai told reporters.
"I don't know how to say it, like (my) heart shakes. First time that I play (world) number six."
Her best tournament result a quarter-final last year in Kuala Lumpur, Luksika, who shares with her idol Monica Seles a compact physique and a double-handed forehand, will next play 39th ranked German Mona Barthel as she bids to reach the third round of a grand slam for the first time.
A gloomy Kvitova said she had enjoyed a "great" off-season but conceded her legs had stopped moving as she tightened up with nerves.
"I was lucky that I won the second set, probably," said the 23-year-old Czech, who has struggled to meet the heights of her 2011 Wimbledon title.
"I think that probably I wanted (to win) too much, and then everything just fell down." (Reporting by Ian Ransom; Editing by Amlan Chakraborty)