Andy Murray defended fiancee Kim Sears over what appeared to be an expletive-laden rant towards opponent Tomas Berdych during Thursday's Australian Open semi-final, saying: "In the heat of the moment you can say stuff that you regret."

Sears was caught on camera apparently swearing as tensions boiled over during a tetchy first set with Berdych serving at 5-3.

Sears appeared to repeatedly swear towards Murray's Czech opponent as the Scot broke back to save the set and make it 5-4.

The expletives were caught on camera and created a storm on social media as to what Sears had actually said.

It was just part of a series of heated moments during Murray's four-set win over Berdych, which took him through to an eighth grand slam singles final.

The build-up to the match had been dominated by talk of Murray going up against his former coach Dani Vallverdu, who is now coaching world number seven Berdych, for the first time.

It certainly seemed to add a fiery edge to the contest and when Murray broke serve to make it 5-4 he turned in the direction of Vallverdu sitting in his opponent's box and let out a huge roar in celebration.

Berdych stared down the court at Murray, who pumped his fist towards his own box - and Sears responded with a fist pump of her own before seemingly mouthing expletives as she glanced over towards the Czech's team.

A 50-50 split screen showing Sears and Berdych's fiancee, the model Ester Satorova, added to the drama with Berdych and Murray soon becoming embroiled in a row over the balls being used.

Berdych complained to umpire Pascal Maria about the quality of the tennis balls, to which Murray responded: "He always does this."

Murray lost the first set but took the next three to reach his fourth Australian Open final, where he will meet either top seed Novak Djokovic or defending champion Stan Wawrinka on Sunday.

Asked later about Sears being caught swearing on camera, Murray replied: "I was told about that.

"Again, when there's a lot of tension surrounding something, which you created, then it's completely normal that, yeah, the whole first set everyone was tight.

"My physical trainer, physio, I'm sure for Dani it was uncomfortable. 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. That's it."

Social media went into a frenzy over Sears' tirade with lip-readers speculating over what she had actually said and many branding her a "pottymouth".

Former British number one Anne Keothavong, who announced her retirement in 2013, retweeted the video and said: "Forget how big the diamond is; THIS is what true love is made of. f****** hilarious!"

The Vagenda Team, from an online feminist magazine, tweeted: "We won't lie, we love a potty mouthed woman, but this is next level."

Radio presenter Georgie Bingham tweeted: "I think I like Kim Sears more now." #pottymouth #dontdothisathomekids."