Kali Meehan, who sparred with Leapai in recent weeks, came agonisingly close to winning the more established WBO title in 2004 when he lost a split decision to Lamon Brewster in Las Vegas.
In three months in 1908, Australians Bill Lang and Bill Squires had, between them, three unsuccessful cracks at wresting the world title from Canada's Tommy Burns.
Now it's the turn of Leapai, who has been branded the Australian Rocky Balboa by Klitschko, who - with a 15cm height advantage - is the Goliath in this matchup.
There was no early sign of global boxing glory for the Samoan-born power puncher, who won just one of his first four professional fights before linking up with trainer Noel Thornberry almost 10 years ago.
Leapai has lost only three of 33 under Thornberry's stewardship and one of his past 23, with 17 of his 21 wins in that latter phase coming via KO.
Thornberry turned around Leapai's career, but it took a while before the Queenslander turned around the rest of his life.
In recent months, Leapai has candidly documented a dark decade during which he had alcohol and drug problems and spent six months in prison for assault.
Before that, a promising league career was nipped in the bud when the former North Queensland Cowboys scholarship holder was banned for five years for attacking a referee.
Having emerged from those tough days, the father of six craves the belt as much for the children he hopes to inspire as he wants it for the million-dollar plus pay day.
"I've been inside [jail], [done] drugs, alcohol and been able to walk away from all that stuff and just go the right path," the 34-year-old said.
"It's so important for me to win this fight just for the kids.
"I've had a pretty bad past and the great lord, the heavenly father, has given me a second chance and I just want to prove it that we can do anything."
A shock win over No1 WBO contender Denis Boytsov in his last bout propelled Leapai into a matchup with Klitschko who is riding a 10-year, 19-fight winning streak.
Thornberry, whose assistant in the corner is his brother and former super middleweight world title contender Rick, spotted Leapai's potential as early as his third paid bout.
"I said to Ricky: 'see that bloke there - if he was serious and wanted to go all the way, he'd probably fight for the world title'," Thornberry said.
"All I had to do was make him as good as he can be.
"I always said to him: 'Listen, you've got strengths; you've got physical strengths - your power - you're very tough. Your weaknesses are experience and your cardiovascular and that all stems from diet, so we changed his diet."
The diet might have changed but the hunger is undiminished.
-AAP
