Heavyweight champion Wladimir Klitschko has dubbed Alex Leapai "Australia's Rocky" ahead of Saturday's world title bout when the challenger tries to complete his rags to riches tale. Leapai sat behind bars in the high-security wing of a north Brisbane jail around the time Klitschko won his first world title in 2006, but now the 34-year-old will box for the champion's WBA, IBF, WBO and IBO belts in Oberhausen, Germany, on Saturday. A bar fight saw the Samoan-born Leapai jailed for six months, "that time still haunts me today". What he gives away in 15cm of height, he is determined to make up for with passion and commitment. "I'm here to make history," says Leapai. "I want people in 100 years to remember that a Samoan-born Aussie came out of nowhere and beat one of the best heavyweights of all time. "It’s been a long road to get to this stage but I will make sure the long ride has been worth it." He earned the right to fight Klitschko by defeating WBO mandatory challenger Denis Boystov in Germany last November and now has the chance to become Australia's first world heavyweight champion. Leapai has a 30-4-3 career record since turning professional in 2004, while the 38-year-old Klitschko is 61-3 with 51 knock-outs. - Underdog who can 'bite' - Klitschko's last defeat was a decade ago after suffering a technical knock-out in Las Vegas against Lamon Brewster on April 10, 2004. Leapai is the overwhelming underdog, but at 112kg, the Australian has the size to at least trouble the champion. "He is the underdog -- but he can also bite," Klitschko told German daily Bild recently. "Leapai will try and beat me with pure violence." Klitschko has questioned Leapai's technique and tactics. "He's Australia's Rocky. He's lacking the experience and I'll use that against him," said the champion. But the Australian is determined to knock the Ukrainian from the top of world boxing. "I have proved that he was just a man like any other -- with two legs and a heartbeat," says Leapai. "It is time for a change of ruler in the heavyweight division and I'm the type of fighter everyone has been waiting for." In the bout's build-up, Leapai was told how to win by a disgruntled former sparring partner of Klitschko. Sherman Williams told German daily Die Welt that he discovered during the recent Austrian training camp that the champion hates taking body shots and advised Leapai to exploit that. "Hit him with left and right shots to the body and then hit him on the chin with the right," said the US-based Williams. "I guarantee that if Alex fights the way I tell him to, Klitschko will throw his arms around like an octopus... and Australia will have a new world champion." Leapai has said he will be inspired by Australia and New Zealand's ANZAC Day, to commemorate their soldiers killed in battle, which falls on Sunday, the day after the fight. But Klitschko has said he has no intention of relinquishing his belt and wants to box on for at least another four years to break Joe Louis' world record of 12 years as the longest reigning heavyweight champion. "I'll demonstrate that I'm the strongest boxer in the world. My mission isn't over yet," said Klitschko. Source: AFP