She sits bolt upright during his matches, jaw tight, living every point her son plays on court.
Win or lose, she clenches her right fist and urges him to keep battling. He'll never look up and see her down-hearted.
Judy Murray is a warrior queen in support of her son. When Andy wins a match, she rises from her seat and punches the air. But when she's watching his big games and he loses, is she to blame?
According to David Yeoman, a behavioural consultant, she may be. He is reported to have said that Andy should consider "asking her to stay away from the tennis courts and the media and let's see if, within a year, he wins a grand slam".
I know a mother's place is in the wrong but isn't this taking it to an extreme?
Yeoman, who has worked with the Scottish Football Association as well as big companies, is a huge fan of Andy and an admirer of Judy's achievements as a coach, mentor and mother. However, he wonders whether Judy's presence court-side stirs negative emotions in Andy about his parents' break-up when he was nine years old.
"How much inner conflict at an unconscious level did this separation have – and still may have – on Andy?"
Or there's this: "A negative emotion from the past, held in the present, is the reason why all the positive thinking will never work. It's not our conscious mind that creates our reality but our subconscious beliefs."
I'd see his point if Judy was just a mother whose hobby was being a camp follower. But she introduced Andy and Jamie, his brother, to the game. She lit the torch of their passion to play. She's been a professional player. She's coached Scotland's national team. Tennis is her life. She knows it inside out.
She's there watching her son for a good reason.
Given Mr Yeoman's thesis, perhaps it's more pertinent to explore Andy's psyche, as far as that is possible. Certainly, during his teens Andy spoke about the distress he felt about his parents' separation and their later divorce. He recounted how he would escape to the tennis court to get away from domestic arguments.
If he spent two nights with his father he would then spend two with his mother. At Christmas, he worried about dividing his time equally between them. It sounds like role reversal, as if he felt too responsible too soon. Like many children of divorce, the break-up of his family left a scar.
But we, as outsiders, can have no idea of the continuing long-term effects or lack of them. No more can Mr Yeoman.
How can any stranger look at Andy or at any person from a distance and do more than guess at what motivates them or limits them? What about his father's presence – or absence from matches? What about sibling rivalry with his brother? What about his romance? What about everything else that has gone into making the man?
What about the big matches Andy has won – and there have been a lot of them – while Judy was in the crowd cheering him on?
What worries me about Mr Yeoman's analysis is the potentially undermining effect it will have. To suggest a mother's presence is an impediment to a son's performance is infantilising. It's emasculating.
It smacks of apron strings, dependency and umbilical cords uncut, of Andy being Andy Pandy.
If you want to win, keep her out of sight is the message from Mr Yeoman.
What tends to be overlooked when we hear about Scotland's tennis ace is that he is already a hugely successful young man. His interaction with his family – whether at a conscious or unconscious level – hasn't kept him from winning. Don't let's forget that along the way he has become a millionaire many times over. It's an immense achievement for someone in his mid-20s, yet he is in danger of being tagged the nearly man.
In fact he has at one time or another beaten all of the players ranked above him. It just hasn't happened when the match was a grand slam final. So far he has gone down at the last – often by frustratingly few points.
He can seem more mortal than Roger Federer, Rafael Nadal and Novak Djokovic, the three above him in the world ranking. They are contained, controlled and driven. Andy's emotions seem more varied. We, the audience, can see him tire and strop and sometimes almost flop.
I have to watch through my fingers when crucial points arise in major tournaments in case his first serve fails or he drives a low backhand into the net. I sometimes wonder how his mother and his girlfriend remain so stoical.
It is frustrating to see him come so close yet not quite take the prize. But we are measuring him against Federer, now number three but still ranked the best player in the history of the game. We forget that Djokovic, the current number one, sat in third position for five years. Did behavioural experts trawl through the entrails of his family life in search of a cause beyond his game?
What about Nadal's uncle who doubles as his coach? Or the Williams sisters Venus and Serena? Their father was a constant presence in the audience when they cut a swathe through international tennis competitions. He coached them just as Judy coached her boys.
Andy has said his exchanges with his mother are mostly normal family chat but if he wants to talk tennis she's informed and receptive. That sounds healthy and uncomplicated to me. But then, like all outsiders, I'm just guessing. Everyone except Andy and Judy is guessing – and if the difficulty is in the unconscious they could be guessing too.
What matters now is that Andy uses Mr Yeoman's observations to his own advantage. I hope he can.
When he was in his teens he said he used his anger about his family's break-up to fuel his aggression on court. If he can get angry enough about this public speculation that mummy is his stumbling block, it might be the fuel he needs to win that grand slam. I hope Judy is there when he does it, pumping her fists in pride like the rest of us.
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