Mario Mola is having to take matters into his own hands with the chasing group's pace still lagging behind that of the lead group that contains both Brownlees and Frenchman Vincent Luis.

The Spaniard has gone off the front of his group as he descends the helterskelter Rio streets.

Moments after the Dutch go out of heat one, the world-record holders and reigning Olympic champions are gone too - the USA have an absolute shocker! Allyson Felix ends up desperately chucking the baton in the direction of English Gardner and it lands between them - game over. 

Spain's Fernando Alarza had a ropey old swim section, emerging from the drink almost a minute off the pace set by Richard Vargas.

He and team-mate Mario Mola are fighting a rearguard action now.

Vincent Luis - the Frenchman who finished second in the test event on this course last year behind the absent Mario Gomez - is part of the lead group on the bike.

South Africa's Henri Shoeman and Ben Kanute of the United States are also up the front.

Their lead over the chasers - including Mola - is up to nearly a minute after the second of eight laps.

"Everything to play for.... There is a bronze medal at stake"

Gill Clarke - Badminton commentator on BBC TV

We are going to a third game to decide this bronze medal...

So close... 21-19 in the second.

Alistair Magowan
BBC Sport in Rio

Image source, BBC Sport

It's blowing about eight to 10 knots across Guanabara Bay so it looks like we'll have sailing today after yesterday's postponement and there are four finals to look forward to.

First up are Hannah Mills and Saskia Clark in the 470, who have an unassailable lead and are in good form this morning after a good night's sleep. 

Clark said she almost starting crying while watching the GB's women's hockey team reach the gold medal match, but she says they are going to race hard in their last competition together and she'll leave the emotion until afterwards. 

Britain's 4x100m women qualify (41.93secs) in second place, predictably behind Jamaica (41.79secs) but well clear of Ukraine in third place. 

The drama in heat once came in lane three, where the Dutch had a horror changeover and finished down in sixth - and it looked like star turn Dafne Schippers was to blame.

Gordon Benson is slightly off the pace, 52 seconds down. 

As a pilot athlete his role is to lead out on the swim, push the pace on the bike, and allow Alistair and Jonny to draft, which conserves energy to exert on the run.

One round to go, and as it stands, Tonia Couch will qualify for the final. She's currently in 11th place with 246.60 points, but it's only a slender lead and her last dive is her least difficult. It has to be spot on to keep her in the top 12.

Annie Emmerson
BBC Sport triathlon expert & former GB triathlete

The descent on this bike course is fairly brutal.

I saw it yesterday and my heart was in my mouth but the Brownlee brothers are good and let's keep our fingers crossed for all of the athletes.

It is a tough, tough course. It doesn't come much tougher than this.

Alistair Brownlee is fourth out of the water with brother Jonny just behind in sixth.

Rival Mario Mola is 16 seconds off the pace.

And the Brownlees are straight on the front of the cycle pack attempting to push the pace and cut the Spaniard loose.

This is going according to plan so far.

Slovakian Richard Varga - who represented his country at youth level as a swimmer - is leading the water, followed by the Russian Dmitry Polyanskiy. 

There have been sightings of two British hats in the top 10. Are there they Brownlee brothers, or has team-mate Gordon Benson got up there among the leaders?

We are about to find out as they near the beach... 

Great Britain's quartet - Asha Philip, Dina- Asher-Smith, Daryll Neita and Desiree Henry - have been drawn in the same heat as a formidable Jamaica team in the 4x100m relay.

Formidable, but not as formidable as it could be.

Double sprint champion Elaine Thompson is not part of the Jamaica team. However Shelly-Ann Fraser-Pryce and Veronica Campbell-Brown are involved.

Dafne Schippers spearheads a Dutch team.

It gets going at 15:20 BST.

"The GB boys didn't win that rally but I am liking their thought processes". 

Gill Clarke, commentator for BBC TV has so far been impressed with the British pair here. 

They are attacking bravely, looking to capitalise on the Chinese players weaknesses and not letting the occasion get to them. 

It's 11-9 to China at the mid game interval in this second set but the Brits are a set up. 

Quick shirt change and a pep talk from their coach and they are ready to crack on with this bronze medal match. 

Aimee Lewis
BBC Sport in Rio

Usain Bolt took over an hour to weave his way through the broadcasters who wanted to speak to him after winning his third 100m Olympic title. What if he had been a shot putter? 

The beefy throwers walk by what is called the 'mixed zone' uninterrupted, almost unnoticed. One athlete is asked by a journalist to stop for a chat but that is about it. For the others, their media duties were over before they'd begun. 

Image source, .

A sea swim is unusual for international Olympic distance events in triathlon, as events usually take place in a lake in ITU events, and the Serpentine in London 2012. The waves, weather, salt water and non-wet suit swim can make or break an athlete's race in triathlon.