Britain book semi-finals place with sudden-death triumph over Argentina
Great Britain claimed a dramatic sudden death victory over Argentina at Deodoro Stadium to book a place in the men's sevens semi-finals.
Dan Bibby struck with a try near the end of five minutes' extra-time to put Britain through 5-0.
Skipper Tom Mitchell saw a penalty kick at goal bounce back off a post just seconds earlier, but Britain kept their composure amid intense pressure.
They will play South Africa in Thursday's second semi-final - the South Africans knocked out Australia 22-5 - with tournament favourites Fiji, who were 12-7 conquerors of New Zealand, meeting surprise package Japan in the other.
Japan, who beat New Zealand on Tuesday in arguably sevens rugby's greatest upset, knocked out France 12-7.
Britain's men emulated the women's team in reaching the Olympic semi-finals, but they will hope to go at least one step better. The women suffered a bronze medal match defeat against Canada.
Britain won Pool C with a 100 per cent record, completing the group phase with a 21-19 win against New Zealand thanks to tries from Mark Bernnett, James Davies and Dan Norton, before a New Zealand comeback from 21 points adrift was ultimately repelled.
And the Argentina clash proved just as nerve-shredding, with both teams temporarily reduced to six players near the end of normal time as Juan Imhoff and Britain's Davies both received yellow cards.
Bibby, though, was the hero, touching down after making a gliding break, to spark scenes of wild celebration.
Reflecting on the New Zealand win, Norton said: " We started out very well and implemented our game-plan. We showed great intensity and came out of the blocks firing.
"We were able to capitalise on our accuracy. We didn't have the ball as much as we wanted in the second-half, but to get the win was an amazing feeling."
Bibby admitted that he thought Britain's run in the competition might have been coming to an end before he struck with the decisive score to sink Argentina.
"I thought that our Olympic dream was over, but luck was on our side," he said.
"When the full-time whistle went, everyone stayed calm. We just kept working hard, and I was just in the right place at the right time.
"As I went over the line, I was just thinking 'don't drop it.'
"I have never played in a game like that. I have played (sevens) three or four years, and I have never been in a 0-0 draw at full-time.
"Fair play to Argentina. They stuck in it and worked us. We kept our composure and got the crucial score.
"We have only been together for 10 weeks, and to fight out there on the field, no matter what nation you are from - England, Scotland or Wales - is what a true team is about."