Australian Open 2018: Johanna Konta knocked out by Bernarda Pera
British number one Johanna Konta suffered a shock defeat by world number 123 Bernarda Pera in the second round of the Australian Open.
The American won 6-4 7-5 to claim only her second win at Grand Slam level.
Ninth seed Konta had reached the quarter-finals and semi-finals on her past two visits to Melbourne Park.
"It's a bit frustrating but I'm still taking good stuff from this," said Konta. "I don't feel, by any means, it's a massive catastrophe."
"I play every event to be there until the end, so I definitely don't want to be going home this early."
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Konta, 26, has now won just three of 11 matches since reaching the Wimbledon semi-finals in July.
She saved four match points on a hot and blustery afternoon but framed a smash on the fifth to give Pera the biggest win of her career.
The 23-year-old lost in qualifying and only made it into the main draw of a Slam for the first time as a lucky loser, after another player withdrew through injury.
The Croatia-born American goes on to face Barbora Strycova in the third round after the Czech 20th seed beat Spain's Lara Arruabarrena 6-3 6-4.
'I was a little uncoordinated today'
Johanna Konta
Johanna Konta fell over twice and struggled with the strength of the sun and wind
Konta could not cope with the pace and depth coming at her on show court two, as Pera attacked relentlessly off her returns and forehand.
The Briton's serve failed to make its usual impact, with the average speed down 9kmph on her previous match as she finished without hitting a single ace.
Despite landing 70% of her first serves, she would end the match having won just 54% of those points, while 14 winners illustrated her struggle to hit through Pera.
"I think my serve definitely let me down a little bit today,' said Konta.
An overhead that was completely missed, followed soon after by a mishit smash on match point, summed up the way her game had unravelled.
"I do think I was a little uncoordinated today," Konta told BBC Radio 5 live.
"I don't think I've fallen over on my own two feet since I was going through growth spurts."
Pera pressure too much for Konta
Bernarda Pera celebrates beating Johanna Konta
Bernarda Pera created 17 break point opportunities while Konta managed only two
It was clear from the outset that Pera was going to provide a far sterner test than her ranking suggested, with a break point going begging in the first game.
A "come on!" from Konta just for holding serve at 3-3 told of the pressure that Pera was applying, and two brilliant returns gave the American the only break of the first set.
The conditions were playing their part, with Konta missing successive backhands from mid-court as the wind swirled, but two double-faults in a row suggested the occasion might finally be getting to Pera as she slipped 2-0 behind in the second set.
That theory was debunked within minutes as Pera tore into another Konta service game, breaking straight back after the Briton telegraphed a poor drop shot.
Konta was under huge pressure now, battling well to save five break points before Pera made the seemingly decisive breakthrough at 4-3.
There was a final flash of resistance from Konta.
She staved off three match points and then broke to level at 5-5, but a desperate service game followed and she would end up flat on her back on the baseline as Pera broke for a fourth time.
With her game creaking, Konta's spirit remained willing at least.
A fourth match point was seen off before Pera finally clinched the win of her life, when the Briton could only frame a smash into the stands on match point number five.
"I just didn't play great," added Konta. "I think it's a part of tennis. It's a part of everyone's career.
"I think you can count on one hand how many perfect matches you have.
"I'd like to think as the season goes on and as I keep putting the work in, that I'll just keep trying to find a way."
Analysis
British number three Naomi Broady on BBC Radio 5 live sports extra
Credit to Pera for outhitting Konta. She was just too good, she served incredibly intelligently, really using the out-wide, swinging lefty serve and if Jo edged over she just aced her up the 'T'.
It's the start of the season and I hope it doesn't knock Jo's confidence too much. I think the Fed Cup will be next so she can get out there and enjoy the team atmosphere.