The Winnipeg skip still has one more shot to reach the final. He will meet Russia’s Evgeny Arkhipov in the semifinal Saturday, with the winner to play Scotland for gold on Sunday.
"The positive we can take out of this is we still have a shot at the gold," Dunstone said after his second loss this week to Scotland. "We've outplayed them both times we played against them. We've been all over them. We hope to play them in the big game."
Dunstone and his team of third Colton Lott, second Daniel Grant and lead Brendan MacCuish, scored three for a 4-2 lead in the sixth end. Scotland moved ahead 5-4 in the eighth on a steal after Canada's last rock picked.
Canada came back with two in the ninth to take the lead going into the 10th end. Smith had a chance for the win but could only score one point on his final throw to force an extra end.
In the 11th end, Dunstone was heavy and wide with his final draw and Scotland scored two for the victory.
"We knew he was going to make his shot and I knew I was going to have to draw to the four-foot and it just didn't work out," he said after the miss.
Russia beat Sweden 6-4 in the 3-4 Page playoff game. Arkhipov has won eight straight games entering the semifinal.
"Russia's been on a hot streak," said Dunstone. "We know this (the semifinal) will be no easier than our game against Scotland, so we'll have to come out firing tomorrow."
Skip Corryn Brown and her team from Kamloops, B.C., did not qualify for the women's playoffs. Scotland was set to meet Japan in the 1-2 game and the Czech Republic to meet Russia in the 3-4 game.