James Lawton: Keane: the ultimate professional who eventually cracked

The background to Roy Keane's ferocious reaction to what he perceived as a slipshod Irish practice session – and his threat to walk out of the World Cup – works against the suspicion that one of the world's most committed professional footballers has flipped clean off his head.

Keane shouted angrily at the Irish goalkeeper coach, Packie Bonner. He threw down a water bottle in disgust. He stormed off to his room, intending to pack his bags for a long, grimly introverted flight home.

It was this World Cup's first authentic, high-octane story. It was the pressure swimming to the surface. But the evidence is that it wasn't simply Roy Keane's crack-up. It was Roy Keane's statement of all those difficult, passionate obsessions which have separated him so profoundly from most of his own generation of players.

Keane's friend and adviser, lawyer Michael Kennedy, yesterday talked Ireland's captain down from the volcano and back into the preparations for the opening game with Cameroon on 1 June, but he could not entirely dissipate the rage that has been building so inexorably over the last few weeks.

When Keane snapped in Japan on Tuesday it was not a sudden brainstorm. It was the expression of that rage. The team's training kit had been left in the hotel. The players had to wait for the arrival of the balls. Keane, living on the edge of aggravating knee and back problems, was appalled at the hardness of the pitch. For several days he had had a smouldering sense that the Irish party's mood was a little too much like that of a gathering of holidaymakers. The requirement of outfield players to man the goals in a five-a-side practice was the final provocation.

The red mist came to Keane as it did on the Monday morning after his Manchester United team-mate Juan Sebastian Veron had made the sloppy error that brought defeat against Middlesbrough at Old Trafford and the team's loss of control of its own destiny in the Premiership race. Keane, it was alleged, had to be dragged off the Argentinian. On earlier occasions the Irishman had bitterly attacked the complacency of his Old Trafford team-mates and rounded on the club's lucrative executive-box customers.

Also simmering in Saipan was Keane's belief that he had been offered to the Irish media as a piece of raw meat after his failure to appear at Niall Quinn's testimonial game at Sunderland. Keane, shattered by his failure to keep United in the title race, worried by nagging injury and drained by the extraordinary effort he had put into Ireland's qualifying bid, told the Irish coach, Mick McCarthy, that he would not be in Sunderland a week before the event. But the news didn't break until the day of the game, the proceeds of which Quinn had long announced would go to children's hospitals. Keane, who regularly visits children's hospitals, was branded as the man who had turned his back on sick children.

At the heart of all this is the reality that the demands of modern football, however extravagant the rewards of it may seem to the public, can create unbearable pressure in certain situations. Keane occupies one of those situations. He is an obsessive over-achiever whose levels of performance and industry have been legendary for some years now. When he flagellates himself so severely, inevitably he expects to see similar self-punishment being administered by team-mates and coaches. When this doesn't happen – at least not to his satisfaction – a great tide of indignation is set in motion.

Keane's friend, the journalist and author and former Irish international Eamon Dunphy, says: "Keane was already seething over the Sunderland business, and if the Irish set-up in Japan was as we have always known it, it is not hard to see him blowing a fuse. No pro ever asked more of himself than Roy Keane and at United he has got used to the highest professional standards. Worried by injuries, he has recently been travelling to France to see a top specialist at the advice of Laurent Blanc, so you can see how he would react to a situation which he considered wasn't right professionally so soon before he goes out to be judged again by the whole football world."

It is here that the professional pride of Keane comes into play so powerfully. Increasingly, he has become a loner at United and Ireland. He has been driven on to his island by the force of his own ambition, and for the point of self-discovery, and the firing of his huge commitment, we probably have to go back to the career-threatening injury of four and a half years ago. He acquired that in a hot-blooded attempt at a revenge tackle. There had been other instances of indiscipline on and off the field, though they had been accompanied by fierce efforts on the field. Now it was though Keane, in his mid-twenties, had grasped the fleeting nature of a footballer's run at the glory. He saw, chillingly, how easily it could all be over. So he has worked, slaved even, to get the most from himself and, by extension, his team-mates.

In Ireland there have been critical comparisons between Keane's absence from the Quinn testimonial and David Beckham's spectacular hosting of a celebrity party in aid of the National Society for the Prevention of Cruelty to Children, which have further opened up seriously smarting wounds. One obvious difference between the players is that while Beckham is relaxed, indeed seems to enjoy the celebrity glare, Keane loathes it. For him there are two realities, the pitch – and the family life to which he now retreats so intently. The price he pays is what often appears to be no more than grudging recognition of the stunning professional values he has come to represent.

While Beckham was "rested" on the bench for six critical games in United's mid-season – partly, it was said, because of the draining requirements of England, Keane fought ferociously to keep the United side on course, while at the same time, and despite injury, almost carrying Ireland to the World Cup. He fashioned the all-important goal scored by Jason McAteer against the Netherlands – and he scored a vital equaliser against Portugal.

But if the Cork man has feelings of patriotism, they are perhaps subservient to his awareness that it is in club football that he shapes the prospects of himself and his family and so, buried deep in the crisis which surely found its expression in Tuesday's emotional rampage, may well be Keane's own sense that maybe he has pushed himself to his very limits.

If he felt too exhausted mentally to make an appearance at Quinn's admirable feel-good festival, how well could he have recharged himself for a six- week stint at the highest level of the game? Also, how heavily does he feel the weight of his responsibility to return United to their old levels of performance when he returns to preparation for next season just a few days after the end of the World Cup?

Keane's critics will no doubt say that this is the terrain of the modern footballer, the ground he has to cover to justify fabulous financial rewards. But they miss the point of Keane's unique acceptance of those demands, his apparently unquenchable need to deliver something commensurate with the prizes on offer.

If the real story of Saipan is the crack-up of Roy Keane we do not have to look too deeply for the cause. It is the anger of a man who may have outrun his own professional environment, simply burned it away with the force of his own need to be a winner. Should this indeed be the case there are questions that need to be answered not just by one anguished player. The whole game needs to answer one of them. It concerns how it is that possibly the world's most motivated footballers should feel so alone, and so angry, on the eve of a World Cup?