In a repeat of last year's final, Brad Jacobs' rink took advantage of a performance two-time world champion Murdoch described as 'sluggish', winning 9-4.
Canada are now the only unbeaten team after five sessions of round robin matches while Scotland are locked in a six-way tie for second place, following their 5-4 extra end win over Denmark earlier in the day.
"Coming out after the extra end in the previous game and then having a 45 minute turn-around, we just weren’t sharp or came out the way we wanted to," said Murdoch.
Jacobs was certainly pleased with the win, although admitted the prospect of a rematch in the business end of the tournament is highly likely.
"We did everything right," he said.
"I have to give a lot of credit to my guys; they played phenomenal. They made it pretty easy on me as a skip.
"We're out here trying to win every game. What I expect is for us to come out each and every time and play really well. I'm pretty sure that if you do that, it's going to take care of itself and it has so far."