Rio 2016: Alistair Brownlee claims Britain's 20th gold medal in the men's triathlon

Alistair becomes the first athlete in history to retain the Olympic triathlon title

Alistair Brownlee crosses the finishing line (Getty)

Not for the first time in this remarkable family duel Alistair Brownlee inflicted necessary hurt on his younger brother Jonathan. Triathlon gold and silver was the result, Alistair creating history with the defence of the Olympic crown he won in London, and Jonathan upgrading from bronze to silver.

It was until the third lap of four on the final 10k run a two-man race then Alistair pulled rank and pulled away. Alistair won in a time of 1:45.01, not that it mattered. He walked the last few meters, waiting for his brother to catch up and applauding him home before breasting the tape.

Both fell to the ground, lay on their back and embraced, to give us one of the celebrations of the games, fraternal rapture to equal that of Laura Trott and Jason Kenny after victory in the velodrome.

It was a Club Tropicana kind of day on the Copacabana beachfront, the turquoise waters obligingly still, a gentle zephyr taking the edge off a punishing sun, fruit punches allround.

And then the pistol went sending a 56-man swarm of lycra plunging into the sea. Like piranhas they were, churning the surface in an almighty thrash to reach clear water. And of course the Brownlees were in the vanguard stretching the field towards the first boy.

On wheels and in water the Britons set the pace, among a leading group that put a minute on their rivals on the eight laps and 38 kilometer race around the Copacabana barrio. Once on foot the Brownlees skipped clear finishing more than half a minute ahead of thrid placed Henri Schoeman of South Africa.

"Every day has been so hard. I have woken up in pain every day." said Alistair, who underwent extensive ankle surgery last year.

"We knew the first two laps on the bike would be crucial. The last few weeks we have been training to commit and boy we did.

"As soon as we got to half way I knew we were going to get two medals and it was just a run for it.

"I was pretty confident we would get first and second but I didn't know which way round it would be. I just had the edge on Jonny but he has killed me in training every day.

"We have been pushing each other to the max. Jonny had the edge and I wasn't sure I would win, I knew had to go through hell and I did."