Tensions boiled over during Andy Murray's Australian Open semi-final victory against Tomas Berdych as the British No 1's fiancee appeared to fire an expletive-ridden blast towards his opponent.
After Murray won a gruelling baseline rally in the first set to claim a break back, Sears was caught on camera apparently mouthing 'F***** have that you Czech flash f***'.
It was just part of a series of heated moments during Murray's 6-7 (6-8), 6-0, 6-3, 7-5 win against Berdych on Thursday.
Sears' apparent foul-mouthed rant came as Andy Murray broke back in the first set
Sears showed her emotion as she watched the action from the stands
A mocked up image of what Sears was reported to have said from the stands
There were no microphones to pick up the 27-year-old’s exact choice of colourful words. But within moments of the uncharacteristic outburst being captured on film, thousands took to social media to comment on it, with some speculating that she had actually said: ‘Take that, you flash f***,’ or even: ‘F****** have it, you Czech f***.’
John Cassidy, a professional lip-reader, insisted that although Miss Sears’ mouth is partially obscured at the start of the utterance, he could ‘clearly’ see her saying: ‘You little f***.’
Asked about his girlfriend’s apparent cursing in the box Murray said: 'I was told about that. When there’s a lot of tension surrounding something which you (the media) created, then it’s completely normal that the whole first set everyone was tight.
'My physical trainer, the 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. In the heat of the moment you say stuff that you regret.'
The build-up to the match had been dominated by talk of Murray going up against former coach Dani Vallverdu, who is now working with world No 7 Berdych, for the first time.
Both had tried to play down that particular dynamic but there was no doubt it added a fiery edge to the match.
Anyone thinking that all would be civil were surely thinking otherwise after Murray broke back for 4-5 in the first set.
After coming out on top in a long exchange, Murray turned in the direction of Vallverdu sitting in his opponent's box and let out a wild roar in celebration.
Murray roars with emotion as he celebrates winning a point against Berdych on Thursday
Murray was clearly pumped up for the game and rose to the challenge as tensions mounted
Murray endured a tough start to the game, losing the first set and clearly was feeling frustrated
Murray celebrates his battling win as he walks off court at the end of the match
Berdych was clearly incensed, giving the Scot a long stare as both players walked back to their chairs.
As Murray sat down, he pumped his fist towards his own box, to which Sears responded with a fist pump of her own before clearly mouthing expletives as she glanced over towards Berdych's team.
Moments later, Berdych complained to umpire Pascal Maria about the quality of the tennis balls, to which Murray responded: 'He always does this.'
Berdych later explained what he said when the two passed at the changeover that seemed to rile Murray up: 'I really remember it well. I say to myself well done Tomas. That’s it. I think I’m allowed to do that when I win a set. What, I have to be worried about every word I am going to say?
I just pumped myself up for winning the first set then sat on the chair. Maybe next time I should stay even more calm, and that’s it. It was a great battle a good match, unfortunately with a bad end for me.'