Alistair Brownlee became the first athlete to defend an Olympic triathlon title ©Getty Images

Britain's Alistair Brownlee became the first athlete to defend their Olympic triathlon title after winning the men’s race today following a stunning performance on a hilly course by Copacabana beach.

Brownlee began the race as one of the main favourites to claim the gold medal in the absence of world champion and London 2012 silver medallist Javier Gomez of Spain, who broke his elbow in a training crash last month.

Attention was instead focused on whether World Triathlon Series leader Mario Mola, also of Spain, could prevent Alistair Brownlee from going back-to-back at the Olympic Games.

However, it proved to be a perfect race for the British athlete as Mola, who would have proved a strong threat on the 10 kilometres run, was left adrift after the 1.5km open water swimming section of the race.

Alistair was joined by his brother and London 2012 bronze medallist Jonathan Brownlee in a 10-man lead group after the swim, with the duo looking to stretch their advantage over Mola and the dangerous South African, Richard Murray, by setting a blistering pace on the bike.

At the conclusion of the 38.5km cycle, the lead group had an advantage of more than a minute on the chasers, effectively meaning that the medals would come from the front pack of athletes.

France’s Vincent Luis briefly threatened to pose a threat to the Brownlees at the start of the run but the brothers pulled clear towards the end of the first of four laps of the circuit.

Alistair maintained a high pace, despite the blistering pace, and left Jonathan behind to go solo to the finish.

The 28-year-old had enough time at the end of the race to collect a British flag from the crowd and walk over the line in celebration, ending in a winning time of 1 hour 45min 01sec.

Britain's Alistair and Jonathan Brownlee set a punishing pace on a hilly course on route to a one-two finish ©Getty Images
Britain's Alistair and Jonathan Brownlee set a punishing pace on a hilly course on route to a one-two finish ©Getty Images

Alistair’s celebrations allowed his brother to finish just six seconds adrift in a British one-two, with Jonathan upgrading from his bronze four-years ago.

"Once I was at the blue carpet and knew I had a gap, and that this probably isn't going to happen again, I wanted to enjoy it,” said Alistair Brownlee afterwards.

“If you can't enjoy having that gap in the Olympic Games, I don't know what you can enjoy.

“I made the most of it."

The result saw the Brownlee brothers become the sixth pair of siblings in Olympic history to achieve a one-two finish in an event.

South Africa's Henri Schoeman claimed his country's first Olympic triathlon medal after overhauling Luis on the run.

He finished 42 seconds behind the winner, with team-mate Murray missing out on the medal places one place.

The women’s race is due to take place on Saturday (August 20).

The United States’ Gwen Jorgensen is the clear favourite to claim the gold medal.