MOTORSPORT SHOWDOWN AT THE MAZDA LONDON TRIATHLON .It has been confirmed today that Jenson Button will compete against a motorsport rival in the Mazda London Triathlon on 2 August 2009. Lewis Hamilton recently backed out of the challenge from Jenson Button but a new challenger, who is currently contending for a title of his own, has stepped in to give Button a true test to see who is the fastest triathlete in motorsport.