British F1 star Jenson Button and 125 motorcycle grand prix star Bradley Smith were separated by less than seven minutes at the end of Sunday's Mazda London Triathlon.
The motorsport pairing exchanged some pre- and post-race banter, but it was Button who finished as the narrow victor after both put in impressive performances.
The 29-year-old F1 world championship leader recorded a personal best time of 2 hours 7 minutes and 2 seconds over the Olympic distance (1500m swim, 40km bike, 10km run).
18-year-old Smith, who stepped in to challenge Button after Lewis Hamilton backed out of the contest, recorded a total time of 2 hours 13 minutes and 36 seconds.
Of Smith, Button commented: "He did very well, he's a fit lad and so am I and it's great to show that at events like this. Our performance demonstrates that we do have to train hard to be an F1 driver or a MotoGP rider and that when we aren't racing, we aren't just at home sitting around and that we do have to be very fit in order to race at our level."
The fastest time was set by Will Clarke, who won the Male Elite class in 1 hour 44 minutes and 29 seconds.
In total, nearly 10,000 competitors took part in the event.
Starting and finishing at London's ExCeL, the course spanned some of the city's most renowned landmarks including the London Eye, Big Ben, and Tower Bridge.
Over £3 million was raised for charity with over 55,000 spectators cheering on the competitors.