John Mullin: I always knew you'd win, Andy. Honest

You may have thought the long years of Caledonian sporting disappointments, sometimes glorious, always grindingly inevitable, were finally swept away in a four-hour, 54-minute extravaganza early on Tuesday.

You may have supposed that we Scots could at last hold our heads high, our self-confidence and national pride recharged in one sensational night in New York. Not me. I have a confession, and the shame of it I will carry to my grave.

We have heard much of bravery this summer. Often deployed with hyperbole, sometimes with condescension, perhaps it should never really be applied to sport. But Andy Murray undeniably showed real guts as he diced with a defeat that may well have had terrible consequences for his career. This, though, is a tale of abject cowardice. Mine.

I first knew of Murray when he won the junior title at the US Open in 2004, and I spoke to a couple of tennis insiders about him. Their verdict, that he was the real deal, was underlined at Wimbledon the following year, when, for two sets, he battered former finalist David Nalbandian. True, he had an irritating tendency to blame others when it started going wrong, and to excuse imminent eventual defeat by theatrical falls with cramp. But I was convinced that he would be a world beater.

He has given us disappointments since. Worse, he's given all those tennis ignoramuses an excuse to chuckle. Not got the bottle. Too defensive. Dour. All clichés. All, perhaps, with some truth to them.

Now, I adore tennis, but I find it almost too tense to enjoy, even watching as a neutral. What makes it such a sensational sport Ω that every single moment matters, and that the margins are so fine – also renders it a form of palpitation-inducing masochism if you desperately want your compatriot to win.

I watched Murray's historic Wimbledon semi-final victory against Jo-Wilfried Tsonga while I was at work, and I could not speak afterwards. Someone made the mistake of coming into my office, and I had to signal them away, because I knew I was very close to embarrassing myself.

I was in bits before the final. I watched in a way I had never quite watched sport before: utterly resigned to defeat. And when he wept afterwards, well…

Then there was the Olympics, and a glorious demolition of Roger Federer. But it was no Grand Slam.

And so we came to the US Open. I was sure he would win. I could see he was ready. I had faith. I briefly considered going to Dunblane for the final. But, in the end, I just couldn't watch it at all. I couldn't bear seeing him lose, and what it might do to him. And so, as millions tuned in, I switched off my phone, and I watched, among other dross, a re-run of The Professionals on ITV4+1.

I told myself I would check the BBC website at 1am after four hours' play, and I watched the minutes tick down. When I did, with sickening trepidation, the headline said he had taken the first two sets and needed one more, but the score beneath showed he had lost the third and was a break down in the fourth.

I went to bed, where I could not sleep, and determined to leave it until 3am before checking again, lest I jinx him. I switched on my phone, saw the website coming up, and held it by my side – rather, I imagine, like a would-be mother waiting to check a pregnancy test – before I could bear to look.

I am overjoyed he won, but ashamed I was too chicken to watch. So whenever anyone talks of Scotland's greatest ever sporting achievement, I will always feel a gnawing sense of self-loathing, for how brave, how enjoyable it must have been to have watched that live? A true snatching of personal defeat from the jaws of a fabulous victory.