James Lawton: Huge finish by little genius – but is he the last of his kind?

As rugby gets bigger and stronger and heavier, perhaps there was a hint of lament

Shane Williams scores his final try for Wales in the final minute in unorthodox fashion on Saturday (AFP)

Coming right at the end of both the match and an astonishing international career, it was the almost eerily appropriate departure of arguably the most relentessly mischievous gnome in the history of his or any other sport.

But then if you wanted another kind of measurement of the mystical impact of Shane Williams – 5ft 7in and 12 and a half stone – in 87 Test matches, it was provided by his tough but adoring coach Warren Gatland with just 10 minutes left.

Gatland, in a last reach to rescue a collision against Australia that was born of nothing more uplifting than corporate opportunism, replaced the imposing teenage wing George North with another candidate to fill the vacuum left so emotionally by the retiring Williams. North stands 6ft 4in and weighs 15st 6lb. The young man who took his place, Alex Cuthbert, is 6ft 6in and 16st 5lb.

After the last of Williams' glory, a 58th try of trademarked invention as the clock was counted down, Gatland dryly defined the nature of the little man's triumph over odds he first inherited in the cradle.

The coach said a rugby player needed skill, speed and size but of course in the case of this particular hero two out of three had proved an ultimately winning equation.

As Williams skipped past the Australian cover and performed a ground level version of a fighter pilot's victory roll, the man beside me leapt to his feet, filled with nearly as much emotion as the hero himself and made a declaration that spoke eloquently for a stadium which had become resigned to a serious case of anti-climax.

"Bloody marvellous," he said and when the 34-year-old Shane Williams is old and grey he might well reflect warmly on the identity of one of his greatest admirers in the huge crowd. He may want to do this because it was Barry John.

Nearly 40 years after his own retirement, John is still seen as maybe the most glorious expression of native Welsh rugby genius but of course, like Williams, he was not exactly a behemoth at 5ft 10in and barely 11st.

Maybe that had at least a little to do with the fervour of his celebration.

As rugby gets bigger and stronger and so much heavier – and Wales appear so well placed to exploit the physiological trend with such as North and Jamie Roberts, Rhys Priestland, the inspiring young captain Sam Warburton and the phenomenally consistent Toby Faletau – perhaps there was also a hint of a lament. Though for what, precisely, did John yearn, however subliminally?

Maybe it was just the tyranny of the clock and the changes it brings, in this case the possibility that players of Williams' inherent brilliance but diminutive stature have never found it so hard to make the kind of mark so unerringly established by folk heroes like Cliff Morgan, Phil Bennett and Jonathan Davies.

If you wanted evidence of this,beyond the departure of Williams, it was produced most compellingly, maybe, by the authority, both psychological and physical, of the reigning out-half Priestland. At 6ft 1in and more than 15st, he is the epitome of the new wave, another piece of genealogical evidence that the door is closing on those who in the past walked through so breezily by showing credentials which spoke chiefly of innate wit and effortless craft.

Gatland was certainly amusing when trawling the permutations of a rugby player's gifts, with, naturally, the small and the slow and the unskilful following home the merely slow, untalented and big.

The debate, unsurprisingly, hardly deflected Williams from the poignant contemplation of the rest of his life without the adrenaline rush that had come, one last time, when he put on the red jersey.

He was overwhelmed by the thought of it when they sang "Land of My Fathers" and it was only with the gravest difficulty that he completed a post-game interview for the benefit of both television and the stadium crowd. Mercifully in the highly charged circumstances such cracking introspection made no claim on his ability to go with a flourish that made it so easy to recall the meaning of his career.

Apart from the joyous expression of his talent to run at and deceive the most rigorous of defences, he reminded us once again of his ability to shut down moments of extreme danger, most notably when he foiled Australia's hard-charging wing Lachie Turner. Williams had no thought for the past or a perhaps diminished future when he forced Turner into touch at the corner flag. He was living, as he did at all those peaks of his career, utterly in the moment.

When he ran in his try so irresistibly, the best of him once again unfurled before your eyes.

One of the greatest of his achievements is symbolised by the fact that at a time when a young Wales have excited such belief in their possibilities, Williams can be credited with so regularly reminding the nation of what was achieved in the past and what might just be recaptured.

Most dramatically, maybe, he did that in Sydney eight years ago when at one point he seemed to have turned an astonishing World Cup game against the All Blacks. He made one superb break to send in Sonny Parker, then scored himself, beautifully, to give Wales the lead.

The Welsh couldn't hold that lead, no more than the one they built so impressively against England in the subsequent quarter-final in Brisbane. But they suggested that they might just do something more lasting at some time in the not too distant future.

Now that Williams has gone, the challenge is neither more nor less challenging, as the Australians reminded us again with still another performance of great competitive character and the exciting promise of 21-year-old James O'Connor.

This reality, however, did nothing to cloud the parting gift of Shane Williams. It carried the inestimable worth of, one last time, moving the spirit of a nation. If you doubt this for a second, you cannot have been standing at the other side of Barry John.