Never write me off, warns sizzling Bolt

'Lightning' strikes again as Jamaican wraps up his meet with third gold

Usain Bolt has warned that people write him off at their peril after the imperious Jamaican sealed another world treble gold despite an injury-hit season.

Bolt anchored Jamaica to victory in the 4x100m relay to add to his wins in the 100m and 200m, trumping his much-touted and controversial American rival Justin Gatlin.