The United States women won their 39th consecutive Olympic basketball game and are seeking their fifth straight gold medal.
Canada managed only eight points in the first period and the outcome was never in doubt as the United States set up a semifinal meeting Thursday against Australia, which defeated China 75-60.
Australia finished 4-1 in Group B, losing only to France during the round-robin phase of the tournament.
Playing in the first of the day's quarterfinal contests, the Americans limited Canada to 16 field goals and 30 percent shooting. Canada turned the ball over 26 times.
Diana Taurasi led a balanced American scoring attack with 15 points while Candace Parker and Sylvia Fowles had 12 each. Chelsea Aubry, who scored 10 points, was the only Canadian to reach double figures.
Australia trailed by one at halftime against China and had only a three-point lead heading into the fourth quarter.
Elizabeth Cambage led a fourth-quarter surge that put the game away. She scored 17 points.
In another quarterfinal, Russia fought off Turkey 66-63. Turkey was one of the surprise teams of the tournament, having been one of the last countries to qualify for the Olympics before finishing second in Group A behind the Americans.