Berlin - World heavyweight champion Wladimir Klitschko defended his WBA, WBO, IBF and IBO belts on Saturday as he out-classed challenger Francesco Pianeta with a sixth-round knock-out to register the 60th win of his career.
Although German-Italian Pianeta, who survived testicular cancer three years ago, came into the fight undefeated in his 29 previous fights, he was outclassed by the 37-year-old champion in Mannheim, south-west Germany.
"I want to thank my opponent, there are a lot of challengers who talk a lot, but he got in the ring and fought bravely," said Klitschko.
His comments were a thinly-veiled dig at David Haye who has constantly tried to lure Klitschko back in the ring, despite the British fighter's points defeat to the Ukrainian in Hamburg in July 2011.
After Pianeta fought on, despite first hitting the canvas in the fourth round, the champion paid further tribute to the challenger's courage.
"After the battle he has had against cancer he deserves respect," said Klitschko.
"He tried everything to hit me, if he had landed one his big punches, I wouldn't have got up."
Pianeta made an ambitious start with one huge right-hand coming over the top of Klitschko's guard but failing to connect, while the champion responded with two heavy jabs which found their target.
Klitschko relied on his jab in the opening three rounds as the challenger landed several heavy shots, but a big right from the Ukrainian put Pianenta on the floor in the fourth round.
From then on, the challenger was struggling to stay in the fight and although he showed plenty of heart by fighting on, he was down again in the fifth, but managed to survive the referee's count.
With his co-ordination clearly compromised, it was only a matter of time before the fight was brought to an end.
With his trainer ready to throw in the towel, Pianeta did not come up again after hitting the canvas after 2mins 52 seconds of the sixth round after a brutal left-right combination floored him for the last time.
"I'm ok, just very disappointed and sad," added Pianeta after receiving treatment in the ring.
Victory gave Klitschko the 51st knock-out of his career, but the last of his three defeats came nearly a decade ago.
For his next fight, Klitschko has been ordered by the World Boxing Association to face Russia's Alexander Povetkin in Moscow on August 31.
Russian promoter Vladimir Hryunov won the purse bid to stage that bout with a staggering $23.33m 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 his 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.