Breanna Stewart drilled a game-high 17 points as clinical reigning champions the United States crushed Canada, 83-43, in record-breaking fashion to make the women's basketball World Cup final on Friday.

They opened with 15 unanswered points and never relented, extending their World Cup win streak to 29 games to set up a gold-medal showdown in Sydney against Australia or China, who play later.

Ever-dangerous Las Vegas Aces' star A'ja Wilson added 15 points and 12 rebounds for the US as they zero in on a fourth straight title and 11th overall. Laeticia Amihere scored eight points to lead a deflated Canada.

It was the biggest winning margin in a World Cup semifinal with Canada's tally the lowest in a last-four clash.

"I was really pleased with our team's attention to detail on the scouting report as Canada has had a terrific tournament," said USA coach Cheryl Reeve. "Canada's a very good defensive team so that was a quality win for us.

"Our goal is to win a gold medal and we are in a position to do that," she added.

USA was the overwhelming favorite in its 10th consecutive World Cup semifinal, having never failed to reach the last four since the knockout stage was introduced in 1986.

In contrast, world No. 4 Canada had got this far just once before, in 1986, when they also crashed to USA.

The Americans' depth, defense and scoring talent was on full display. They have killed it inside all tournament, sinking 55 points a game in the paint ahead of the semi-final, while punishing errors.

It was a similar scenario against Canada, who had taken big strides under coach Victor Lapena but struggled against the speed of their opponents.

"Congratulations USA, they played amazing from the beginning. When you play against USA in a semifinal, it's clear you must be perfect or they are going to break the game in 10 or 15 minutes," said Lapena.

"But I'm very happy to have this kind of experience for my players, especially the young players, to see what it means to play against such amazing players."

USA's 15 straight points at the start gave them an immediate stranglehold and Canada never recovered, needing five minutes to get off the mark.

While the US shot 79 percent, Canada could only manage 11 percent as they fell 27-7 behind after the first quarter.

The margin only grew in the second frame to 45-21, with Seattle forward Stewart at the forefront.

They put on another 22 points in the third quarter to build a huge 38-point buffer going into the final stretch before cruising home.