World heavyweight champion Wladimir Klitschko takes on undefeated challenger Francesco Pianeta on Saturday in a busy summer for the Ukrainian champ with a bumper pay-day againstRussia's Alexander Povetkin looming on the horizon.

The 37-year-old Klitschko will defend his WBA, WBO, IBF and IBO belts inMannheim, south-westGermany, against German-Italian Pianeta who survived testicular cancer three years ago and has a record of 28 wins and one draw. Pianeta beat 48-year-old former world champion Oliver McCall on points last year, then laboured to another points win overSouth Africa's Francois Botha, 44, but is eager to face the reigning champion.

"I will bust my backside to get those belts. I am sure that everyone is beatable," said the 28-year-old, who has a tattoo bearing Julius Caesar's boast -- "veni, vidi, vici" (I came, I saw, I conquered). Unlike Klitschko's recent victims,Poland's Mariusz Wach, Frenchman Jean-Marc Mormeck andBritain's David Haye, Pianeta has already faced Klitschko, having been a former sparring partner.

"He knows what he's getting himself into and that's why he's confident that he can win this fight," said Klitschko's trainer Johnathon Banks. "That's what's going to make this fight a good one." With 143 sparring rounds under his belt in training, Klitschko is looking for the 60th win of his career with 50 knock-outs and he has no plans to add to his three defeats, the last of which came nearly a decade ago.

Klitschko has said he will do "everything for a clear win" having been ordered by the World Boxing Association to face Povetkin in Moscow on August 31 at the city's 60,000-seater Olympic Hall. Russian promoter Vladimir Hryunov won the purse bid to stage that bout with a staggering $23.33 million bid last week.

The Ukrainian is entitled to 75 percent of that figure, which would give him a career-high $17,250,000 purse.

Povetkin is the 'regular' WBA champion and Klitschko the governing bodies' 'super' champion -- an honour bestowed on him when he added the WBA belt to his three others with a points win over Haye in 2011. Now Klitschko and Povetkin are obliged to fight in order to leave just a single WBA belt-holder.

The two former Olympic champions were due to clash twice before but Povetkin pulled out in 2008 because of injury and then backed out a second time in 2010. Klitschko has banned any questions about Povetkin and opted to face Pianeta in a voluntary defence of his titles. "It looks like I'm looking past him (Pianeta) already before the fight which is not OK, but it's not my decision," he said. "It's not my call. I'm just following the rules and I'm not going to be distracted."