Vladimir Klitschko stopped former sparring partner Francesco Pianeta inside six rounds in Mannheim on Saturday to retain his four world heavyweight title belts.
The Italian-born challenger briefly ruffled the champion by landing a couple of punches in the second round but apart from that appeared out of his depth.
Klitschko twice sent his opponent to the canvas in the fourth round before the referee called a halt to proceedings eight seconds from the end of the sixth as Pianeta took a pounding.
The 37-year-old Ukrainian extended his unbeaten run to 18 fights, his last defeat coming when he challenged Lamon Brewster for the WBO title in 2004.
Overall, he has won 60 of his 63 fights, including 52 within the distance.
Klitschko holds the IBF, IBO, WBO and WBA crown and his older brother Vitali holds the WBC crown. The two have pledged not to fight each other.
Pianeta, who at 1.93 meters is five centimetres shorter than his opponent, was previously undefeated with 28 wins and one draw.
"He started well and he tried to take the fight to me, he fought with great courage," said Klitschko.
In the other boxing note, former world heavyweight champion David Haye will fight German Manuel Charr on June 29 in Manchester, the Briton's promotion team said on Sunday.
Haye, who lost his WBA belt in July 2011 to Ukrainian Vladimir Klitschko before beating Dereck Chisora 12 months later, faces Charr who has won all but one of his 24 professional bouts.
Heavyweight boxing world champion Vladimir Klitschko (L) of Ukraine lands a punch on his Italian-born challenger Francesco Pianeta at the SAP arena in Mannheim, May 4, 2013 (Photo: Reuters)
Ukranian heavyweight boxing world champion Wladimir Klitschko (L) walks away after defeating his Italian-born challenger Francesco Pianeta (R) at the SAP arena in Mannheim, May 4, 2013 (Photo: Reuters)
US actress Hayden Panettiere, girlfriend of Ukrainian heavyweight boxing world champion Vladimir Klitschko, reacts to Klitschko's victory over his Italian-born challenger Francesco Pianeta at the SAP arena in Mannheim, May 4, 2013 (Photo: Reuters)
Ukrainian heavyweight boxing world champion Vladimir Klitschko celebrates with his brother Vitali (R) after defeating his Italian-born challenger Francesco Pianeta at the SAP arena in Mannheim, May 4, 2013