They beat the record of six, set by the Swedish men in their victory over Finland in Salt Lake City in 2002, and equalled by the Canadian men, also against Finland, in 2006.
Team Muirhead held two points as the skip prepared to push her last stone towards the house, and with the perfect weight she cleared the only US stone in the vicinity to seal the seven points.
“For the girls to score seven on their first Olympic win is fantastic, that was definitely the turning point for us in that game," said Muirhead, who admitted to a few nerves as she delivered the stone that secured the magnificent seven.
“I love it when my team play a fantastic end and leave me easy shots like that. You will always take a nose hit for a seven and that was definitely the game changer.
“It was a routine shot for me. That is why we practice twice a day for a couple of hours to make these key shots. They are just like any other shot and we practice so when the pressure comes on you make sure you nail that shot because a there are no second chances out there.”
Muirhead had said her rink needed to respond to their defeat against European champions Sweden and they did in style, with lead Claire Hamilton, second Vicki Adams and third Anna Sloan all boosting high percentage against their luckless rivals.
"To not have the hammer in the first end and still manage to convert it in the next two ends was good and then take advantage in the fourth end and come out with the seven to virtually end the game," added Muirhead.
“It was important that we came out tonight to get that win on the board after yesterday and that was definitely more like Team Muirhead.
"The four of us really pulled together and played well. Things aren’t perfect just yet, we can still get better. In major championships we seem to start off slightly slow and get better and better and we can certainly build on that.”
However, it doesn't get any easier for Great Britain's women with Canada's gold medal favourite Jennifer Jones next up, a scalp the British skip claimed at the recent Continental Cup in Las Vegas.