Watching a rerun of Kevin Pietersen's unbeaten 91, off just 65 balls, against Australia in a one-day international in 2005, was to see an innings of raw and uninhibited genius. His batting was calculated before an explosion that was truly astonishing: flicking straight balls over mid-wicket for six; crashing flat-batted straight drives with awe-inspiring power; and obliterating perfectly competent balls with scant regard for reputation. Undoubtedly, it ranks as one of the finest ODI innings ever played by an Englishman; wrestling back a match that they had threatened to lose through some brainless batting and a failure to seize the initiative.
The most astonishing thing about Pietersen's knock was the apparent inevitability of it all. This is not just a trick the rerun plays on us: coming just after he had blazed three centuries in South Africa and won the Man of the Match award against Australia in the Twenty20, Pietersen seemed invincible, able to do no wrong. His strike-rate suggests he must have been going at full-pelt throughout when in reality he was restrained for the first half of his innings.
Three years on, innings of the sort he played in those first and scarcely believable international knocks are increasingly hard to envisage. His strike-rate in the recent one-day series against New Zealand - who possess a significantly worse bowling attack than either Australia or South Africa did then - was a modest, and inadequate, 73.
Since then, Pietersen has seldom scaled the magnificent heights of those innings of 2005. He has lost some of his sheer 'wow factor'. Alas, it was inevitable. In these days of specialist analysts, it was inevitable opponents would find areas of weakness, and would not continue to feed his flamingo shot to mid-wicket. Pietersen, too, has been unable to maintain the enthusiasm and relish for the contest that characterised those glorious early months of his international career. That was also inevitable: the relentless international schedule simply does not allow otherwise.
Pietersen is essentially doing as well as anyone could have hoped, and only last Test played a superb and priceless innings. Nonetheless, it is easy to long for the sheer fearlessness, unorthodoxy and raw power of those first steps in international cricket. His maturity has come at a price.