LONDON (AFP) - One of China's three best hopes of winning the men's singles title suffered a sensational opening day setback when the fifth-seeded Chen Long fell to an outsider in the first round in the world championships at Wembley. Having made a determined fight-back against Kevin Cordon, the world number 36 from Guatemala, Chen failed to convert three match points and lost 21-19, 8-21, 27-25. The 22-year-old from Hubei also suffered the frustration of twice losing vital points in the closing stages when he was adjudged to have made contact with the shuttle on the wrong side of the net. On the second occasion, which put him 15-17 down in the decider, Chen complained to the umpire, gestured to his coach, and walked frenziedly in circles, causing a minute's delay before resumption. He did well to regain his composure and to earn match points at 20-19, 21-20, and 23-22. But each time Cordon produced his best badminton and edged towards his best ever win. Much of the time he played Chen at the net, knowing that the Chinese player was sometimes fearful of lifting the shuttle and providing opportunities for his deceptive left-handed smash. That restricted Chen's options, and Cordon was at least the seeded player's equal in the front court exchanges. Chen had afterwards regained an ability to be philosophical about what happened. "Before the match I never thought I would lose," he said. If Cordon continues to play at this level, he could progress to a last 16 meeting with Marc Zwiebler, the German who reached the semi-finals of the All-England Open in March.