Muirhead's rink came from behind against winless Chinese skip Wang Bingyu to triumph 8-5 and move into joint second in the overall standings with three wins and one defeat so far.
Trailing 4-2, the contest turned on its head in the seventh end as Muirhead scored four then succeeded with a draw for two in the ninth after Wang picked up a point in the eighth.
It ended 8-5 with Scotland now unbeaten in two after responding to a 11-2 loss to Sweden on Sunday afternoon with a 9-2 victory over Germany in the evening with Muirhead's confidence rising.
"It was solid out there," said Muirhead. "We had a good chance in the first end but she played a good shot. But giving up a one is not a disaster.
"It was a big decision in the seventh end. I tried not to think about it too much, I just put the brush down and played it.
"It's one of those shots. If you make it, you've got a good chance of winning the game, and if you don't, you've got a good chance of losing.
"I said that if we could get a two up on the board at any point, it would put pressure on them, but to get a four was a bonus, a real turning point.
"We're just missing a few key shots; it's just little bits here and there. I'm happy, sitting on three and one and everything's coming together nicely.
"We've got Japan next and that's going to be another tough game. We need to come out with the same kind of fight."
Canada skip Rachel Homan and Japan's Satsuki Fujisawa also moved to three wins and one loss with the former defeating Russia 5-4 and the latter seeing off Germany 6-4.
However Russian skip Anna Sidorova, the reigning European champion, bounced back to defeat Switzerland, who had earlier lost 9-0 after six ends to Sweden, next time out 8-4.
Sweden sit top of the standings with four wins from four and skip Margaretha Sigfridsson put her rink's good form so far down to simply starting well in each of their contests.
"The secret is to really get going in the beginning and to play quite easy. That is our strategy in the beginning of the games," she said.
"Sometimes we are slow starters but we have worked on that for a few years now and I think we're getting there.
"We need to keep on playing well, feeling good and getting rest when we can. It's an intense week with many games so we just need to keep on focusing."
China also returned to the ice but saw their winless streak continue as they handed Italy, who earlier beat hosts Latvia 7-5, their second win of the day 7-6 after an extra end.
Elsewhere the USA were rarely troubled against Denmark leading 3-0 after three ends and then 6-3 after seven before ending 7-6 victors with their record now two wins and two losses.
