The head of state posted the greetings on his Facebook page.
"I congratulate Oleksandr Usyk on a convincing victory over Marco Huck. Keep it up, champion!" Poroshenko wrote.
Kyiv Mayor Vitali Klitschko also greeted the Ukrainian boxer on the victory, the mayor's press service reported.
"I congratulate Oleksandr Usyk on his victory! Oleksandr, you are a fighter! The fight was not easy, so it was more interesting and the victory is more valuable. Thank you! Your victory is a victory of Ukraine!" Klitschko said.
WBO cruiserweight champion Oleksandr Usyk defeated German Marco Huck during the World Boxing Super Series tournament in Berlin on Saturday night. The Ukrainian defended his WBO title and advanced to the WBSS semifinals. Usyk will face the winner of a fight between Latvian Mairis Briedis and Cuban Mike Perez.