Alistair Brownlee became the first man to win consecutive Olympic triathlon titles after storming to gold on the Copacabana with brother Jonny completing a Team GB one-two.
With Alistair repeating his feat from London 2012, the silver medal is an upgrade for Jonny who came home in third four years ago.
Both Brothers finished the 1500m swim in the front group before heading a charge of 10 bikes for the 40km ride.
France’s Vincent Luis broke clear with the Brownlees at the start of the 10km run before Alistair’s pace dropped both Luis and then his brother as he claimed gold. South Africa’s Henri Shoeman completed the podium line up with bronze.
Team GB's other entrant, Gordon Benson, did not complete the race after crashing on the seventh lap of the eight-lap cycle race as he left the event grazed but otherwise unhurt.
“Obviously it’s very special to retain the title,” said Alistair.
“I’ve trained as hard as I can this year and executed it on the day. The records or whatever isn’t the big thing for me it’s about turning up on the day and winning the race.
“Maybe the enormity of it all will sink in over the next few weeks but I’m just pleased I turned up and Jonny did it as well.
“The odds are it won’t happen again.
"Four years is a long time to Tokyo but I don’t think we should be thinking about that at the moment.
"I think we should just enjoy what we’ve pulled off today and be really appreciative that these last three months of training went so well and we managed to get the race to go our way.”
Jonny was equally delighted but admitted he would have liked to have pipped his brother to the gold medal in their friendly rivalry.
“In the race I had a very good swim and on the bike I felt great and controlled. I might have done a bit too much work on the bike but when we got to the run Alistair was too strong for me and these hard races suit him a bit better than me.
“A bit of me thought ‘here we go again’ but I was confident I’d hold onto second but he got his gap and it just stayed.”