Ukraine's Vitali Klitschko retained his WBC heavyweight title on Saturday night after beating previously undefeated challenger Kevin Johnson of the United States (22-1-1, 9 KOs).

The bout at the PostFinance Arena in Switzerland's Bern lasted all 12 rounds with the judges unanimously scoring in favor of the 38-year-old Ukrainian 120-108, 120-108, 119-109.

"Dr. Ironfist" Klitschko (39-2, 37 KOs) retired in November 2005 with a knee injury, but announced his comeback last year. He regained his WBC belt in October last year in Germany, defeating Samuel Peter, dubbed the Nigerian Nightmare.

Earlier in the year Vitali said he wanted the Klitschko brothers to have all four of the heavyweight titles.

Vitaly's brother Wladimir Klitschko (53-3, 47 KOs) is currently the WBO and IBF heavyweight world champion, while David Haye of Britain holds the WBA title.

MOSCOW, December 13 (RIA Novosti)