ASTANA – Japan's Takanori Nagase was a surprise winner of the men's under-81kg title at the world judo championships in Kazakhstan on Thursday. The 2013 World University gold medallist upset Frenchman Loic Petri, the 2013 world champion in the final in Astana. Nagase distracted Petri in ground fighting by manoeuvring for an armlock before switching into a hold. He kept Petri pinned on his back long enough to score the maximum ippon -- equivalent to a knock-out in boxing. It was sweet revenge for Nagase, who lost to Petri a year ago in Msocow for bronze. It was Japan's fourth title from eight events at these championships as the Land of the Rising Sun continues to dominate the sport it gave to the world. Georgia's 2014 champion Avtandil Tchrikishvili lost to Victor Penalber of Brazil for bronze.