Vitali Klitschko, the world heavyweight boxing champion, is one of the most successful boxers of his generation but his toughest fight yet may just be in its infancy.
In his 16-year professional career, the Ukrainian held world heavyweight belts during three separate spells, most recently the World Boxing Council title from 2008 until he vacated it at the end of 2013. His professional record is impressive: 45 wins from 47 fights.
The challenge he faces now is likely to be a great deal more taxing, though. The 42-year-old has been involved in Ukrainian politics since 2005 and is to run for mayor of Kiev. Of all the situations, Kiltschko has been in, none have been more volatile than the current political situation in Ukraine.
His story is nothing short of remarkable; he is as far removed from the traditional boxing stereotype as one could imagine and both he and his younger brother, Wladimir, have had to overcome numerous obstacles in order to dominate the heavyweight division.
They had a nomadic childhood, living in various Soviet republics because of their father's job: he was a colonel in the Soviet Union Air Force. Klitschko was originally an amateur kickboxer and a story about his days in the Ukranian kickboxing team provides an insight into his future attitudes.
In 'Klitschko', a documentary about the lives of the brothers, Vitali recalls being selected to compete in the United States. Until then, he had been told that America was "the enemy" and that they would not enjoy going there.
When he arrived to compete, it was unlike anything he had seen or imagined. The shopping malls were mesmerising and the range of choice enthralled him. Why do these people need so many pairs of shoes, he wondered. Surely, you only need one? And he tasted Coca-Cola for the first time. This trip began to open his eyes to a democratic society.
When Klitschko was 13, he turned to boxing, quickly realising that he had an aptitude for it, and he turned professional at the age of 25.
The fall of the Berlin Wall in 1989 followed by the collapse of the Soviet Union two years later, had a huge impact on the landscape of professional boxing. Boxers who had previously been trapped behind the Iron Curtain suddenly had the opportunity to fight around the world for money.
The Klitschkos were among some of the first afforded this chance to move from Eastern Europe to the West. Both Vitali and his brother elected to move to Germany, where they would remain for most of their careers. Unusually for the sport, the Klitschko brothers have retained almost complete control over their destinies, both in the ring and financially. Again, bucking the trend, both Vitali and his brother have PhDs in sports science and can speak four languages. They set up the Klitschko Foundation to help under-privileged children and are also Unesco Ambassadors.
It is many of the qualities that Vitali honed as an athlete which may prove to be invaluable in his next career as a politician. In 2010, Klitschko, nicknamed Dr Ironfist, formed the Ukrainian Democratic Alliance for Reform (UDAR, which translates as 'punch') and two years later was elected into the Ukrainian parliament.
Klitschko firmly believes that he can lead his country towards a better future. Last year he announced that he would run for president and was one of the most influential leaders of the deadly street protests in Kiev in February which toppled pro-Russian president Viktor Yanukovych's regime. However, Klitschko announced last month that he had decided against contesting the presidential elections on May 25, instead throwing his support behind Petro Poroshenko, with the former boxer now running in the Kiev Mayoral elections, to be held on the same day. It is now likely that both men will cement powerful positions in Ukraine's new government.
It seems likely, though, that Klitschko will, in the future, make a bid for the presidency. He is popular in Ukraine and has no connections with the 'old guard', a stance which works in his favour. He may be wealthy but has made his money honestly, which has earned him trust from his supporters.
Klitschko's experiences as a boxer have shown him just what is possible for Ukraine as a nation and he has urged the people to come out and protest, saying he will "face bullets" with them if it comes to that. Just as when he was a boxer, Klitschko believes that "there is no victory without a fight, and we will fight".
His boxing mentality persists and, as in the ring, he will never give up. While the two domains could not be more different, the character traits cultivated in Klitschko's first career will serve him well in his second.
It would be a brave man who bets against Klitschko achieving success in the political arena, as he did in the boxing ring.