TOKYO (AFP) - Olympic gold medallists China won a fifth straight men's title at the world gymnastics championships Wednesday, crushing Japan's bid to return to the top after 33 years. China collected 275.161 points and Japan finished second at 273.093 after their key man and defending all-around champion Kohei Uchimura fell from the horizontal bar in their final rotation. The United States finished third by just one hundredth of a point behind Japan. Japan trailed China by 0.609 points into the sixth and final rotation. But Yusuke Tanaka and Uchimura, Japan's last two performers in their final event, horizontal bar, failed to re-grasp the bar and fell to the mat. China scored steadily in their final event, floor exercise. Zou Kai, the Olympics floor and high bar gold medallist, punched the air when he completed China's last exercise while Uchimura waited to begin his routine after Tanaka's failed performance. Zou scored 15.600 points, the day's best on the apparatus. "I knew before I began my floor exercise that we had won because Japan made a major mistake," said Zou. "If the second Japanese gymnast did not fall from the bar, it would have stressed me out," he said. "If Japan did perfectly, they would have won the gold. They were unlucky." China have won the last four world men's team titles as well as the 2008 Beijing Olympic gold. The Japanese men were 2004 Athens Olympic champions, but their last world team title came in 1978. "Frankly, I am really disappointed," the 22-year-old Uchimura said. "I realised again that we would never win if we make mistakes." "After seeing Yusuke fall, I knew we could never catch up with China even if I performed perfectly. I lost my concentration a little bit," Uchimura said, who is aiming for an unprecedented third straight all-around world title. "All of us knew the point difference before floor exercise. We knew we would win if we performed normally. That might have led to Yusuke's mistake as he was a newcomer. I did not feel any pressure but my team-mates might have." Japan and the United States clashed head-on in the same rotation group as the top two qualifying teams. After four rotations, Japan topped the rankings with Russia and China in second and third spots, and the United States in fourth place. But China, a squad studded with Olympic and world champions, took the lead after the fifth rotation as horizontal bar title holder Zhang Chenglong scored 16.200 in the event and Zou collected 15.933.