Canadian goaltender Charline Labonte stopped all three shots she faced in the shootout.
After Wickenheiser beat American goaltender Jessie Vetter, Labonte stopped Gigi Marvin for the victory.
She also turned away Julie Chu and Natalie Darwitz. Vetter stopped Canada's first shooter, Sarah Vaillancourt.
Wickenheiser had a goal and two assists in regulation and Canada also got goals from Kelly Bechard, Vaillancourt and Gillian Apps in front of a near-capacity crowd of 15,003 at MTS Centre.
Jenny Potter, Krissy Wendell, Marvin and Darwitz replied for the U.S.
Labonte stopped 25 shots for the victory. Vetter, playing in her first game against Canada, turned away 26.
Canada meets Finland on Monday (8:30 p.m. ET).
Canada, the U.S. and Finland finished first in their respective pools and play each other to determine which two countries advance to Tuesday's final (8:30 p.m. ET).
The team that finishes third plays for the bronze medal against the winner of the round robin between group runners-up Sweden, China and Switzerland.
The U.S. and Finland meet Sunday.
Canada came from behind twice Saturday to tie the game in the first two periods.
A hooking penalty to Apps and a cross-checking minor and misconduct by Bechard late in the third period had Canada two men down for 46 seconds. Canada killed off both penalties to send the game into a 10-minute overtime.
Potter of the U.S. went into the box twice during the extra period for hooking and kneeing, but Canada couldn't convert either power play into the game winner.
In another game Saturday, Germany beat Kazakhstan 3-0.
Canada had trouble early in the game working the puck out of its own zone under pressure from the U.S.
The Canadians also gave up three odd-man rushes in the first period that didn't bear fruit for the U.S., thanks to stops by Labonte and a blocked shot by Cheryl Pounder.
Apps tied the game with her first goal of the tournament at 14:57 of the second period. A Delaney Collins shot deflected off a U.S. skate and Apps corralled the rebound.
Labonte then made a sprawling save on Marvin to preserve the tie heading into the third period.
Wickenheiser pulled the Canadians within a goal at 12:23, wiring a high shot over Vetter's shoulder on a pass from Apps.
Darwitz gave the U.S. a two-goal cushion with a power-play goal at 11:03. Wendell got Labonte to commit to one side of the net, which made room for Darwitz to finish the play on her stick side.
Marvin restored the U.S. lead at 6:52, putting a hard shot upstairs on Labonte, after Vaillancourt's power-play goal at 3:21 deadlocked the game 2-2.
Wendell tipped Natalie Darwitz's shot from the faceoff circle by Labonte's glove at 17:47 of the first period to give the Americans a 2-1 lead heading into the second period.
Potter tied the game at one at 7:49 when she banged in a rebound on a shot by Kristin King.
Canada scored first at 1:21 when Bechard got lumber on Katie Weatherston's centring pass from the blue-line. Vetter retracted her pad too soon as the puck slide by her.