RIO DE JANEIRO >> There was no question coming into the Olympics that the U.S. women's basketball team could score.
With the offense struggling at points Friday for the first time, the Americans turned up their defensive effort to dispatch Canada.
Maya Moore scored 12 points and the U.S. clinched the top seed in the group with an 81-51 win over its northern neighbors.
"I think we played really hard today on defense," guard Sue Bird said. "Everyone's been talking about our offense, but it's been our defense that has been the most consistent. Tonight was a good example of that. It wasn't that we couldn't score, but we just weren't scoring at the rate you saw in the first three games. It was our defense that was there for us to rely on."
The Americans (4-0) had been scoring at a record pace, topping 100 points in each of their first three contests — the first time a team's done that at the Olympics. But they couldn't get into an offensive rhythm for the first 20 minutes against Canada.
The U.S. was out of sync, throwing the ball away on fast breaks and missing open shots. Canada, which already had sealed a berth in the quarterfinals for the second consecutive Olympics, wasn't intimidated. The teams had played an exhibition game before the Olympics started and Canada lost by 40, never recovering from a slow start.
It was the U.S. that struggled early in this one. The Americans only scored 18 points in the first quarter, their lowest scoring output in any period in Rio. Canada only trailed 18-16. That's when the U.S. turned up its defense. For nearly 10 minutes, the Americans held Canada without a basket and slowly extended their advantage.
Canada got its only bucket in the second quarter on a three-point play by Nirra Fields with 39 seconds left in the period and the U.S. led 36-22 at the half. Coach Geno Auriemma said the team did nothing special during that stretch other than just play hard defensively.
"Our defensive effort was great," said Moore, who scored all of her points in the first half.
Diana Taurasi helped the U.S. get some separation against Canada. She hit two 3-pointers in a row to start an 8-0 run that gave the Americans their first 20-point lead of the contest. She now has 18 in the Olympics, breaking her own team record of 15 set in 2012.
Canada could only get within 15 the rest of the way. Miranda Ayim scored eight to lead the Canadians.
Despite the loss, Canada (3-1) has already won more games than in any other Olympics. The Canadians hope to win the country's first medal in the sport. They finish pool play Sunday against Spain, trying to secure second place in the group.
"It's huge, we're here to make history," Fields said. "We already made history and our goal is to really just medal. Finish the highest we can. Playing against Spain is a very important game and we'll be ready for it."
The victory was the Americans' 45th straight in the Olympics. They are halfway to a sixth consecutive gold medal.
While the U.S. roster is stacked with some of the greatest players in UConn's storied history, including Moore, Canada has its own Husky in Nurse, who will begin her junior year at Connecticut this fall. Nurse came into the game leading the team in scoring, but had a rough contest against the U.S. and her college coach Auriemma. She scored just three points, missing eight of her nine shots.
Nurse's game probably could be summed up in one play: She had the ball stripped by Moore near the top of the key and then chased the former UConn great down the court as Moore converted a layup.
"We all have those moments, kind of welcome to the next level moments. I had them, she'll have them," Moore said. "And then when she's in my position, she'll be giving it to the next generation. So, it's one play. We all have to get our pockets picked. But I was trying to be aggressive. I'm sure it'll be something she uses for the next game."
In other games on Friday, Serbia won its first contest ever in the Olympics, beating China 80-72. A victory over Senegal on Sunday would advance Serbia to the knockout round. Spain routed Senegal 97-43 in the late game Friday, setting up a pivotal game against Canada on Sunday.