Alistair Brownlee carries his bro over the finish line after he almost passes out

British Olympic gold medallist Alistair Brownlee has helped his near-unconscious brother Jonny take second place at the final of the world triathlon series.

One of the most dramatic finishes in triathlon history featured Jonny initially coasting to the win of the men's elite race.

But then he started to succumb to the fierce heat that has marked the worlds in Cozumel, Mexico.

First Brownlee staggered and then slumped to the ground.

Alistair abandoned his duel with South African Henri Schoeman to help his younger brother.

Schoeman won the race and Jonny was second, with Alistair alongside him for third.

There was a protest against the Brownlees' finish, but under triathlon rules assistance from other competitors is allowed.

Jonny needed medical attention afterwards and the result cost him the world series title.

Had he held on, Jonny would have taken the series lead from Spaniard Mario Mola.

But Mola finished fifth and that was enough to secure the overall series win.