Kim Sears
Kim Sears is seen swearing after Murray loses the first set in the Australian open.AFP / Getty Images

Kim Sears has become a target for vile Twitter trolls after her foul-mouthed outburst was caught on camera.

The 27-year-old has been subjected to an online backlash from Czech tennis fans after she was seen mouthing expletives during a tense moment in yesterday's Australian Open semi final.

She is alleged to have referred to Murray's opponent Tomas Berdych as a "Czech flash f***."

A hate-fuelled Facebook fan page has been dedicated to the blonde, comprising offensive posts stating she "deserves a couple of slaps" for her rant during the match and should die.

Posting on the unofficial Facebook page, Pavel Kratochvil, from Prague, wrote: "Die. you s***."

Karel Zelezny added: "F***ing English B****! Such a f***ing p****. You deserve someone to give you couple of slaps."

While David Carbol added: "Little stupid cow. I'm czech." In other posts Miss Sears was called a "bad sport s***", a "silly stupid girl" and a "British f***."

The messages were posted after Murray beat the world number 7 sending the Scot into the final. 'Kim Sears' was trending on Twitter for 24 hours after the incident.

Last night Andy Murray defended his fiancée for her unexpected tirade. "When there's a lot of tension surrounding something which you (the media) created, which you created, then it's completely normal.

"The whole first set, everyone was tight. My physical trainer, physio, I'm sure for Dani it was uncomfortable," he explained.

"Even Tomas, who very rarely says anything on the court, there was tension there for him, as well. Yeah, in the heat of the moment you can say stuff that you regret. And, yeah, that's it."

As the video of the uncharacteristic outburst went viral, Sears was branded 'a legend' and 'hilarious' on social media.

She also received words of support from German tennis player Andrea Petkovic who tweeted: "I love Kim Sears so much," while comedian Jack Whitehall said: "Anyone else find Kim Sears incredibly sexy when she's angry?"

Murray proposed to his girlfriend of nine years in 2014.