Sweden's Fredrik Loof and Max Salminen won the Star Medal Race to upset the favourites and take the gold medal in a thrilling finale.
Having trailed overnight leaders Iain Percy and Andrew Simpson (GBR) by 12 points ahead of the Medal Race the Swedes won by four seconds over Hamish Pepper and Jim Turner to overcome the Brits who finished eighth.
The Brits had to finish sixth or better to guarantee gold but in a tense final run Norway's Eivind Melleby and Petter Morland Pedersen, America's Brian Fatih and Mark Mendelblatt and Brazil's Robert Scheidt and Bruno Prada finished less than two seconds ahead of the Brits squeezing them into eighth and down into silver medal position. The Brazilians subsequently fell into bronze medal position.
The Swedes were worthy winners and sailed their own race from the start with only the bullet on their mind, Loof said, "It was a dream come true. We were happy for the silver but the gold came instead.
"We knew the other guys were under more pressure and stress than us, so we really had nothing to lose and just wanted to sail a good race. We were looking back but we knew we had to do our best. We sailed a brilliant race; we were fast downwind and upwind."
For Percy and Simpson they were unable to defend the title they won at the Beijing 2008 Olympic Games and were disappointed not to defend their overnight lead, "It's frustrating,"
said Percy. "We tried our hardest and did well in the regatta. At the moment, it does hurt. It's a testament to how well we sailed.
"We sailed 10 good races. There's a big luck element. We can't blame anyone but ourselves, but at the same time we were really proud."
Scheidt and Prada were the pre-race favourites and had mixed emotions picking up the bronze medal. Scheidt said, "I am a little sad losing a position but, at the same time, very happy to get a medal. We would have wanted a bit more."
1.Fredrik Loof and Max Salminen (SWE) - 32pts
2. Iain Percy and Andrew Simpson (GBR) - 34pts
3. Robert Scheidt and Bruno Prada (BRA) - 40pts
4. Eivind Melleby and Petter Morland Pedersen (NOR) - 63pts
5. Hamish Pepper and Jim Turner (NZL) - 70pts
Follow all the action on the ISAF Olympic Live Blog
which will bring competition updates and instant reactions to the action on the race course. Fans can check in and ask our media team questions to get the very latest information. The blog will start one hour before racing each and every day of the competition.
ISAF Olympic Website