Vladimir Klitschko wins to retain four title belts

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.