Usain Bolt is usually quick enough not to have to worry about what's going on over his shoulder.
On this occasion though, he was caught very much by surprise.
Basking in the glory of his latest victory - 200m gold at the Beijing World Championships - the Jamaican goes over to lap up the adulation of the crowd.
One very eager cameraman, riding a segway, is keen to get as close as possible to Bolt. Too close, in fact. Colliding into him, Bolt is sent crashing to the floor along with cameraman and his segway.
Very unfortunate, but very, very watchable...
