Eve Muirhead guided Team GB through a phalanx of permutations and into the Olympic semi-finals, dramatically guaranteeing a shot at a medal.
Britain needed to beat the Russian Olympic Committee to give themselves a chance and hope Switzerland beat Japan and Sweden beat South Korea.
They downed Russia 9-4 and watched on nervously as the Swiss prevailed 9-4 and then Sweden held off South Korea's 'Garlic Girls' 8-4.
Muirhead’s rink squeaked through thanks to the Draw Shot Challenge - curling’s equivalent of goal difference - an average score taken from single stones thrown before all nine round robin games.
Britain's draw shot score was 10 centimetres better than Canada's and one centimetre better than Japan's, sending Muirhead through in third, Japan fourth and knocking Canada out.
Nails were bitten to the bone by Muirhead, Vicky Wright, Jennifer Dodds and Hailey Duff who now face Sweden in Friday night’s semi-finals.
“I'll be honest, I was following the other matches,” said Muirhead, who found out her ultimate fate on a TV screen in the post-match interview area.
“I knew that our job was to win and that was our first priority, but it’s very hard to concentrate fully and I had one eye looking across at the games.
“I hope I didn’t show it! You’ve got to keep an eye out when you know you’re either in or out.”
The quartet also benefited from the draw shot challenge at the Olympic qualifier in December, where they sealed their spot at the Games at the last possible opportunity.
Having missed out on the first six qualifying spots at last year’s World Championships, Muirhead has orchestrated a remarkable turnaround in her team who will now at least play for bronze.
“This team has a lot of resilience,” she said.
“We've come from a squad of nine people to a team that have won the Europeans, qualified for the Olympic Games and now have a semi-final spot.
“I don't think you can turn your back on this team. We've shown a lot of character, a lot of grit and determination and we fully deserve the spot.”
Opening with the hammer advantage against the Russians, Muirhead made a superb start and two inch-perfect draws into the button saw Britain jump 2-0 ahead.
Alina Kovaleva responded with a takeout to halve the deficit and looked poised to steal in the third end before Muirhead nailed a high-risk takeout to restore the lead.
Ice conditions seemed to disrupt Britain’s play at times, particularly that of third Wright whose shot accuracy was well below her usual standards, hovering at 60%.
But they hung tough, Muirhead drawing into an empty house to make it 4-2 at halfway before ROC missed a glaring chance for two, taking out their own stone with the hammer.
Muirhead held on and scored four in the penultimate end and fists bumped with an end to spare, with Sweden’s steal of one in the ninth helping the pendulum swing Britain’s way.
"I always say that the round-robin is one competition and the playoffs is another one," said Muirhead. "There are things we need to reset but I definitely think that as a team, we are a playoffs team.
"We've proven that we're capable of winning that gold medal as a group, so we will go hard tomorrow."
Muirhead and Swedish skip Anna Hasselborg have shared many a battle over the years, with the Swedes taking 10-5 semi-final victory at the last Olympics en route to gold.
"This will be my third Olympic semi-final but I don't want it to go the way that 2018 went," said Muirhead.
"That was tough but I believe in us as a team, with the amount we've practiced, the amount we've trained, the amount we trust each other and enjoy it.
"All we can do is curl the way we have been all week and if we carry on that and carry on the momentum, we definitely won't be far away."
Britain beat Sweden at November’s European Championships and then claimed a surprisingly one-sided 8-2 win in their second round robin game.
Jubilant head coach David Murdoch said: “I just feel like the girls don't really have much pressure on them.
“The games they've lost, they have just been a small inch here and there.
“The question for Sweden is: you've won before and can you win again? For us, in some ways we're the underdog. You know what happens sometimes with that.”
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