Canada's surging under-19 women's basketball team continued its remarkable run at the world championships in Chile on Wednesday.

Twins Michelle and Katherine Plouffe of Edmonton combined for 36 points as Canada upset the United States 64-52 and secured first place in its group and an undefeated record.

Michelle Plouffe had 24 points and eight rebounds while Katherine added 12 in the battle between undefeated teams. Wumi Agunbiade of Pickering, Ont., added 15 points and nine rebounds.

"Michelle Plouffe is a very mature and smart basketball player that has helped the whole team maintain composure throughout the tournament," said Canadian coach Rich Chambers.

Canada's 6-0 record after two rounds is the best for any national basketball team heading into the quarter-finals of a world championship. The Canadians' best-ever finish at the women's under-19 tournament was fourth in 2009 in Bangkok, Thailand.

"We did a great job defending the guard play of the U.S.," Chambers said. "Our forwards made their entry into offence very difficult."

The Canadians led 20-10 after the first quarter and 29-23 at halftime. They took a two-point lead into the fourth before pulling away from the Americans (5-1) over the final few minutes.

Ariel Massengale had 17 points for the Americans, who outrebounded the Canadians 38-33.

Korissa Williams of Windsor, Ont., was a big presence on the defensive end, with a team-high five steals and seven rebounds.

Canada's opponent in Friday's quarter-finals is still to be determined, but Chambers said the game will be his team's toughest test yet.

"All eight teams that are left could win the world championships," the coach said.

The Canadians had already clinched in a berth in the quarter-finals with Tuesday's victory over Japan.