Cory Thiesse and Korey Dropkin scored in five of the seven ends for the US, including a single steal in the first and a two-point steal in the second to set them on their way at the Gangneung Curling Centre.

Chiaki Matsumura and Yasumasa Tanida replied for Japan with a single in the third, but the US seized control of the match with a perfect tap through a port for two in the fourth.

A fifth-end steal put the US 6-1 in front before Japan pulled a point back in the sixth.

A nose hit from Thiesse in the seventh earned a further two points for the US, prompting a concession from their opponents.

"I can’t even believe it, I’m definitely still speechless right now," she said afterwards.

"It definitely hasn’t sunk in yet, but it’s incredible.

"I’m just so proud of my partner, we had a great week and it’s just incredible."

Tanida admitted "our performance wasn't great and they played really well".

Earlier in the day, Norway's Martine Rønning and Mathias Brænden secured bronze by beating Canada's Sochi 2014 Winter Olympics gold medallist Jennifer Jones and Brent Laing 6-2.

The teams swapped singles in the first two ends, before Norway went 2-1 up in the third and secured a steal in the fourth.

Another steal followed for the Norwegians in the fifth, before Jones made a game-saving tap for Canada in the sixth on their power-play to pull the scores back to 4-2.

Rønning made a draw to the button on her team's power play to go 5-2 in front with one end remaining, and Jones' ambitious take-out attempt in the final end missed to add another single to Norway's win.

Mixed doubles has featured as a curling medal event at the Winter Olympics since Pyeongchang 2018, with a World Championship in the discipline first held in 2008.

Thiesse and Dropkin's success marked the first time an American pairing have taken the title.

Matsumura and Tanida's silver was also a first medal for Japan at the World Championship.