Seon Okazawa and Tomoya Tsuboi became Japan's first boxing world champions on Friday after they respectively won the men's welterweight and bantamweight titles in Belgrade.
Tokyo Olympian Okazawa, 25, was on the back foot during his final against Omari Jones but landed right jabs and left straight punches in the third and final round to edge the American 3-2 on the judges' scorecard.
"I just thought I had to believe in myself. I'd have lost if there'd been a doubt," said southpaw Okazawa, who had hurt his left shoulder during his semifinal.