It is not just his size which makes Vitali Klitschko stand out in the proud history of world heavyweight champions.

The 6ft 8in Ukrainian possesses all the obvious physical attributes to conform to the stereotype expected for success in the land of the giants.

But the other common misconception of fighters as young delinquents forced through an absence of anything else in their bleak lives to find fame and fortune through their fists does not apply.

Klitschko is the first fighter with a PhD to hold the world heavyweight title, and is more likely to engage in discussion over Ukrainian politics than the prospect of bashing somebody's head in.

This week, the 33-year-old Klitschko has had plenty on his mind as he prepares to defend his WBC title against Danny Williams in Las Vegas next Saturday night.

He admitted he came close to postponing the fight and flying home to participate in demonstrations surrounding the disputed presidential election.

As a national hero in Kiev and a fervent supporter of the opposition candidate Victor Yushchenko, Klitschko felt he had a duty to try to make a difference.

Instead Klitschko, who became a doctor of philosophy of sports science at Kiev University in 2000, was persuaded to stay in the United States while his brother Wladimir jetted back.

The elder Klitschko had realised that the best contribution he could possibly make was to retain the world title and provide an inspiration for his people's continuing struggle.

Klitschko and his brother, the sons of a Ukrainian air force colonel, looked special from the moment they made their first tentative starts in the world of kick-boxing.

It always seemed likely that one or both of the brothers would make it big and Vitali belatedly secured the title he had dreamed about in April this year with an eighth-round knockout of Corrie Sanders.

He had returned stronger from his experience against Lennox Lewis in June 2003, when he led on the scorecards before bad cuts prompted the doctor's intervention in round six.

It was a major blow for a man so unused to setbacks in either of his parallel careers as both student and scholar of the noble art.

After all, this is a fighter who upon turning professional whizzed straight into the pages of the Guinness Book of Records by winning his first 27 fights by stoppage.

Nineteen of those vanquished opponents were dispatched inside the first six minutes of action and only one saw the bell for the start of the sixth round.

The seemingly unstoppable Klitschko held the WBO version of the heavyweight crown, winning it with a devastating second-round stoppage of Herbie Hide in London in June 1999.

And such was the powerful phenomenon of himself and Wladimir that they were winning over even the cynical American fight public as realistic contenders.

But Klitschko's biggest setback occurred in Berlin of the following year when a shoulder injury forced him to retire during his defence against Chris Byrd.

Not only did he lose his WBO title but also the respect of some observers, who felt Klitschko had made a conscious decision to quit.

It is a stigma which Klitschko has failed to entirely shrug off to this day, despite fighting on through a mask of blood until prevented from doing so against Lewis.

And it is one he will probably have to live with until he has clambered up and won from a position where all seemed lost.

Which is hardly a regular occurrence in the world of Klitschko, whose five wins after Byrd were at least enough to re-establish him as the leading contender to Lewis.

And subsequent to the Briton's retirement and Klitschko's vacant title win over Sanders, it was the Ukrainian who was elevated above the other heavyweight title claimants as Lewis' genuine successor.

It is a tag Klitschko clearly deserves as the outstanding heavyweight in the world today, and one of those rare fighters who really does almost have it all.