Hamburg - Wladimir Klitschko has earned the 17th defence of his world heavyweight crowns with a fifth round knock-out of Kubrat Pulev on Saturday to secure the 53rd KO of his career.
The 38-year-old inched closer to the legendary Joe Louis' record of 25 heavyweight defences when he put the Bulgarian down for the fourth time after two mins, 11 seconds of the round.
Klitschko dominated the fight in one of the most impressive displays of his career as he prepares to become a father next month with his girlfriend, actress Hayden Panettiere, a star of hit US series, "Heroes" and "Nashville".
The Ukrainian champion paid tribute to his countrymen in their ongoing military struggle against Russia after the bout in his adopted home town of Hamburg.
"I want to dedicate this victory to my compatriots in the Ukraine, who are experiencing difficult times," said Klitschko, whose brother Vitali, the mayor of Kiev and an ex-world champion, was in his corner.
"Pulev put in a good performance and I give him respect.
"He made it hard to land the left hook by staying out of range, but I managed to land a lot of punches and I'm glad it worked out in the end."
The Ukrainian retains his IBF, IBO, WBA and WBO belts to remain the undisputed heavyweight champion of the world after the 63rd victory of his career and used his left hook to devastating effect.
Pulev was twice on the canvas in the first round after an explosive start by both the world champion and the International Boxing Federation's (IBF) mandatory challenger.
The Bulgarian was quickly on his feet, grinning and balancing on one leg in a bid to prove he was unaffected, but Klitschko was soon on top.
Klitschko put Pulev on the canvas with a fierce left hook in the third round, as a cut opened under the challenger's left eye, but he survived referee Tony Weeks' count.
It is more than a decade since Klitschko's last defeat, to Lamon Brewster in April 2004, and the champion was clearly on top by the fourth round.
Klitschko caught Pulev flush in the face with a left hook early in the fifth round and another ended the fight as the Bulgarian went down for the fourth and final time.
The defeat was the first of the 33-year-old's career after 11 knock-outs in 20 victories and despite his pre-fight promises, the challenger failed to trouble the champion.
"I'm happy with myself, but I think Klitschko had a bit of luck," said Pulev before being taken to hospital in Hamburg for treatment.