Volodymyr Zelensky, the president of Ukraine, congratulated Oleksandr Usyk for defeating Anthony Joshua.
On Saturday night in Saudi Arabia, Usyk of Ukraine defeated Joshua.
Usyk defeated Joshua twice to retain his IBF, WBO, and WBA titles, and Joshua lost on a split decision.
Zelensky responded by stating that Usyk's triumph was significant and vital for Ukraine.
"Difficult but extremely vital and necessary win," he wrote in his tweet.
"Retaining the title of the undisputed world champion is a sign of the fact that everyone who belongs to the Cossack family will not give up theirs, will struggle for it, and will undoubtedly prevail."
Usyk, meanwhile, dedicated his win to the Ukrainians fighting for their nation.