IT is the measure of the precise standing of a hero if he is given a standing ovation when going to the toilet.

It is a measure of the hero when he withstands a barrage and emerges victorious. It is a measure of the champion when he strikes when it matters most.

By all these measures Andrew Barron Murray makes the 6ft10ins John Isner look like Jimmy Krankie at a crouch. This is no swipe at a frankly admirable American, it is, rather, a testimony to what faced a 27-year-old Scot in front of a home crowd expecting victory in a clamorous atmosphere where one can shrink or grow according to character.

Murray had to both control his nerves and hold his nerve in the Emirates Arena yesterday afternoon. He faced an extraordinary trial at the hands of Isner who threw down 28 aces and offered the Scot a first break point after one hour and 26 minutes of a compelling match.

The Wimbledon champion, of course, took it with a shot of high technique and some impertinence. He lobbed Isner on the run which in level of difficulty is on par with knocking the ball over the Finnieston crane and landing it on a soup plate.

Shortly afterwards, Murray went for what our colonial cousins call a comfort break. He was cheered all the way out of the arena and to the facilities. He was two sets up by then and on the way to completing a 7-6 (4), 6-3, 7-6 (4) victory in two hours 31 minutes that takes Great Britain into a home quarter-final against France in July.

He had completed this feat in the face of withering fire but with a certainty of purpose. Murray had to remain calm, hoping that the storm would blow itself out before it tossed the tie back into uncertainty.

He did so. He survived seven break points in that testing first set and saved them all. The crucial moment that testified to the difference between the great and the merely very good came in the first point of the first tie-break. Isner made a double fault. It was his only such blemish in the match. It was enough to lose the set, perhaps even the match.

Murray had thus made the crucial breakthrough and that lob in the second set was enough to stretch the lead. The third set went to a tiebreak and, again, Isner stumbled on the first point, Murray smashing an overhead.

Thus was the battle won. Thus was the tie secured. James Ward could subsequently retire after winning the first set against Donald Young and head straight to Indian Wells where he has to play in qualifying.

Murray, too, heads for America but as world No.4 now and with a game that is secure technically, physically and mentally.

There will be those who insist this was a scrappy victory but a match against Isner would not be pretty if he was playing mixed doubles with Kylie Minogue. Isner hits hard but not often.

But he has lost all four matches against the Scot for a reason. Murray is a brilliant defender with Jim Courier, the USA captain, later saying that his traits make him an even more difficult opponent for Isner than Novak Djokovic, the world No.1.

But it was Murray's obduracy, almost Scottish thrawnness, that was the most commendable aspect of his game yesterday. It took Isner six aces to win the third game. The Scot's retrieving was relentless and adept but it was his ability to persevere that made the difference.

His strength yesterday was his defence as his serve was placed under pressure by Isner and his second serve could only be watched by the partisan crowd through their fingers.

Murray, too, had a right to be concerned as Isner started with the sort of violent strokes last seen on the Three Musketeers. Isner later said he felt Murray's apprehension but he also felt the force of the Scot's retorts on the racket.

On the pantheon of Murray victories, this will never be listed as the most spectacular but it must have carried a huge satisfaction. He was playing a No.20 in the world who was determined to go broke and not be broken.

Murray maintained a composure in the most testing moments and this allowed him to endure the most brutal of the Isner blows.

The greatest satisfaction must be that he performed, again, under immense pressure. From Thursday onwards, his team mates and most of press have nominated him as the winner of two points.

This is understandable in that he is a grand slam winner and of a different class even to Isner who once was a top 10 player. But this expectation can be a burden, particularly when 7700 lusty throats are bellowing for victory.

Yet Murray was professional amid the frankly hysterical. He even had the temerity to win the match with an ace, almost reminding Isner of the aphorism that those who live by the big serve can die by it.

He celebrated with some restraint before shaking the hands of all his team mates and support staff.

There was a subsequent rush on to court to jump high and pump his fist repeatedly.

But in between there was a long hug with Leon Smith, the Great Britain captain. "He's done a very good job over the last four or five years," said Murray. "He's created a very good team atmosphere, team spirit, got the right people in the right positions to help the players as much as possible. He's left no stone unturned in terms of preparation for all of the ties. I would say that it's a very important thing as a captain or a manager or a coach to have people around and be able to listen to their advice and take it on board, and he's done that extremely well."

The captain is from Clarkston and two of the players from Dunblane but the unexpected victory came from a Londoner in Ward. This was not a victory completely made in Scotland but it is one that was created in a distinctly Caledonian atmosphere.

Anyone for more tennis? Scotland craves a return of the Davis Cup and soon.