Video has emerged of the moment Stan Wawrinka has an on-court row with Roger Federer's wife - believed to be prompted by her calling him a 'cry baby'.

It comes after the revelations that Federer and Wawrinka had a furious 10-minute row in a private room backstage at the O2 Arena after Saturday's Barclays ATP World Finals semi-final match.

They were both determinedly putting on a united front for the Swiss Davis Cup team – just as the moment that caused their weekend fallout in London appeared to be identified. 

Roger Federer is about to serve before his compatriot Stan Wawrinka looks to the sidelines at the O2 Arena

Warwinka then points to the side of the court, and says: 'Not just before the serve', before pacing on the spot

Umpire Cedric Mourier gestures and attempts to calm Wawrinka down by saying 'No, Stan, no'

After Mourier attempts to calm Wawrinka, he continues pacing and pointing towards the sideline

With the match at a crucial stage, Wawrinka halts as Federer is about to serve

 

Footage from their tense semi-final shows an angry Wawrinka pulling away from receiving serve at 5-5 and deuce in the third set, because of something off-putting he has heard.

It comes from the direction of where Federer’s wife Mirka was sitting, with the words ‘cry baby’ seemingly uttered.

This tallies with what well-placed tournament sources said occurred and which has also been reported in French sports daily L’Equipe.

The sequence of events at that point shows Wawrinka glancing to the courtside supporters’ bench as Federer prepares to serve.

He then pulls away from receiving the serve, turns to his right and with his racket pointing there says: 'Not just before the serve.' 

Federer's wife Mirka is alleged to have called Wawrinka a 'cry baby' before the point was played

He is admonishing someone – apparently Mirka - for talking too loudly as he gathers his concentration. It does not appear to be the first time he has been distracted.

A woman’s voice then can just about be made to call out ‘cry baby’ in response. 

The flustered umpire Cedric Mourier leaps in at this point, sensing the danger of the situation running out of control.

'You hear what she say?' says Wawrinka down the court in the direction of the umpire’s chair and Federer.

Mourier’s imploring calls of 'No, Stan, no' seems to calm matters, and he settles back down to receive serve again with one last look to his right.

While both he and Mirka are multi-lingual it is likely they would communicate in English as French is his first language, and she comes from the Swiss-German speaking part of the country, having first emigrated from Slovakia.

For a seasoned professional like Wawrinka to react to goading from any old member of the crowd is extremely unlikely, and the direction of what he is saying shows he is talking to someone at ground level.

The commentary of Mirka, as ever doing whatever she can to support her husband, was a big factor in the enormous spat that followed between the two men after the match (which Federer won). Tour officials ushered them into a room that had been set up as a gym to sort out their differences. 

They travelled separately to Lille on Monday, Federer taking his private jet and Wawrinka the Eurostar.

However, Federer posted a picture of the team with their arms around each other, including him and Saturday’s opponent. 

 

Federer Tweeted 'It's great being with the boys again', alongside a picture with Wawrinka and the rest of his Swiss team-mates.

And the Swiss No 2 tweeted the same picture just minutes later, in what looks like an attempt to smooth over the dispute.  

Federer won Saturday's match 4-6, 7-5, 7-6 at the O2 in London, but his victory has been overshadowed by the fallout.   

Tour officials decided that the best thing was to push them alone into a private room that had been converted into a gym area, as there is no communal locker room at the arena. 

While the dispute is not believed to have become physical, a heated 10-minute row ensued in which both aired their grievances against the other.

In what had been an unusually feisty and high quality semi-final, Wawrinka had four match points and served for the match at 5-4.

According to French television, Wawrinka was picked up saying: 'She did the same thing at Wimbledon.' 

Federer and Wawrinka have traditionally got on well together, and of course it is not unusual in sport for things to happen in the heat of the moment and then to be smoothed over with the passage of time.

And now they know they face a race against time to prepare for the Davis Cup final, something Federer has never won and which he desperately wants to add to his collection.

As they will be up against a fresh French team, playing in front of 30,000 supporters in a football stadium with accompanying atmosphere, and having to make the transition from indoor hard court to clay, there is plenty stacked against them. Their only hope is to have a united front, given the circumstances.

John McEnroe spoke of the dispute on American television, but he seemed unaware of the extent to which it has escalated, according to those Sportsmail has spoken to.

Another cause of tension in matches between the two is said to be the presence in Federer's box of Swiss Davis Cup captain Severin Luthi, who coaches the world No 2 along with Stefan Edberg.

Although doing his best to stay impartial in these encounters, it is not hard to see why Wawrinka might resent his team competition captain siding with his rival when it comes to their head-to-head combat. 

Ultimately the Swiss No 2 was unable to finish the job off and was denied a place in the final of the prestigious year-end championships, with well-placed sources saying he was furious at the intervention of Mirka.

While the undoubted row between the two men is a distraction, it was not the main cause of Federer pulling out of Sunday night's final, although the tension it caused is unlikely to have helped. 

The Swiss master, drained by the physically and mentally exhausting match against Wawrinka, sustained a pull in his back and clearly did not wish to risk it ahead of the Davis Cup final.

Federer usually manages to avoid controversy and his wife says little in public, despite playing a major role in her 33 year-old husband's phenomenal career.

Those who know her speak of someone quietly formidable and determined who behind the scenes helps organise the incredibly busy life of her spouse, with whom she now has two sets of twins.

A former player herself, when she was known as Miroslava Vavrinec, she reached a career-high singles ranking of 76 and met the soon-to-be superstar at the 2000 Sydney Olympics. However, she had to retire from the sport with a persistent foot injury and has since channelled her energies into helping her husband become the global icon that he now is.

Aside from maintaining his fitness and training regime and having four young children, Federer also has a large portfolio of sponsorships and has his own personal charitable foundation that he attends to.

Mirka, who married him in 2009, is said to be a key component in making his life run like a Swiss clock to keep the success going. 

She is also known to have steely side, and it seems that is what has led to the fallout with Wawrinka that could be a threat to Switzerland's Davis Cup dreams.