Watch: One brother helps the other over triathlon finish line

San Miguel de Cozumel, Mexico: Britain's Alistair Brownlee came to the aid of his exhausted brother Jonny to help him across the line in a dramatic finish to the ITU Triathlon World Series here.

Just a few hundred meters out from the finish of Sunday's event, younger brother Jonny, the Rio Olympic silver medallist, was on course for victory when he began to weave out of control, appearing on the point of collapse.

Alistair, 28, who won gold at the Rio Olympics ahead of Jonny, was in third place and came from behind to the aid of his brother, propping him up and pushing him over the line in second place.

Victory would have given Jonny, 26, his second world title but as he struggled over the dying metres, South African Henri Schoeman overtook to win the race, made up of a 1.5km swim, followed by a 40km bike ride and the 10k run.

"Not how I wanted to end the season but I gave it everything," the younger Brownlee tweeted after race in hot and humid conditions, saying he had suffered from dehydration. He also tweeted a picture from his hospital bed where he received treatment, giving the thumbs up and saying he was okay.

Alistair, who finished the race in third place, said he would have done the same for any other competitor.

"It was a natural human reaction," he was quoted by the BBC as saying.

Jonny Brownlee's near collapse allowed Spaniard Mario Mola, who finished fifth, to claim the world title with the Briton in second place.

(Credit: AFP)