SYDNEY >> Alyssa Thomas and her United States teammates were tested for the first time in the World Cup by a physical Serbia team.

After a slow start, the Americans used a dominant run spanning the half to take control of the game and reach the semifinals again.

Thomas had 13 points, 14 rebounds and seven assists to help the U.S. beat Serbia 88-55 in the quarterfinals of the women’s World Cup on Thursday.

“I think you expect every team’s best punch in the first quarter,” Thomas said. “We just had to settle into the game and once we settled in, then we were really able to break away.”

Kelsey Plum scored 17 points and A’ja Wilson added 15 to lead the Americans (6-0), who will face the winner of Canada and Puerto Rico in the semifinals on Friday.

“They played super physical, more physical than we’ve seen the entire tournament,” Plum said. “Credit to them. I felt that early-on their pressure bothered us a little bit, but we were able to kind of get under control.”

The Americans had run through pool play, winning by 46.2 points per game and hadn’t faced any kind of challenge. Serbia (3-2) wasn’t afraid though, going right at the U.S. The Serbians scored the first basket of the game — marking the first time the Americans trailed in the tournament.

It was back-and-forth for the first 17 minutes, with the U.S. failing to go on any major run. Then, with 2:59 left in the half and the U.S. up by five, Kahleah Copper drove to the basket and was fouled. She landed hard on her hip and had to be helped off the court by the U.S. training staff. Copper, who has been a sparkplug for the U.S. in her first tournament, didn’t return.

“It’s too early to tell,” Reeve said of the extent of Copper’s injury. “We’re getting her some imaging and we’ll have information later.”

Plum replaced Cooper and hit the two free throws, starting a 12-0 run to close the half as the Americans led 50-33 at the break. Thomas had 13 points, six rebounds, four assists and two steals in the opening 20 minutes.

The U.S. extended its run to 20 straight points in the third quarter before Serbia finally ended a nearly 8 1/2 minutes drought with a 3-pointer by Yvonne Anderson. That cut the deficit to 22 points. Serbia didn’t get much closer after that.

Anderson led Serbia with 14 points.

Betnijah Laney went down hard early in the fourth quarter on a put-back. She left the game and sat on the bench for the rest of the game.

“She took a hard fall,” Reeve said. “She was in the locker room afterwards and I think in her case it was a little more of it took the wind out of her.”

The victory was the 28th in a row in World Cup play for the Americans, who haven’t lost since the 2006 semifinals against Russia. The Soviet Union holds the World Cup record with 56 straight wins from 1959-86.

After going unbeaten in pool play again, the U.S. reached at least the semifinals for the 12th consecutive tournament, dating to 1975. That year completed a cycle in which the Americans lost 14 games combined in four tournaments. They’ve only lost five games since.

PICASSO IT WAS NOT

The U.S. had dominated the paint even without Brittney Griner, outscoring its opponents by an average of 60.8-24.4 in pool play. Serbia held a 20-16 advantage at the half and ended up outscoring the Americans 28-26 in the game by constantly having two or three players inside to clog up the middle.

“It’s one of those things you got to live with,” Wilson said. “Hopefully these next couple of games we can get back to owning the paint. Serbia did a great job of locking it down.

TRIPLE-DOUBLE WATCH

Thomas, who had a triple-double in each of the last two games in the WNBA Finals, fell just short again of getting the first one at the World Cup since Erika Dobrovicova in 1994 for the Slovak Republic against Spain. Assists and rebounds weren’t kept before 1994. Thomas had 14 points, nine assists and seven rebounds in the opener against Belgium.

TIP-INS

Jewell Loyd returned to the U.S. starting lineup a game after resting according to the team. She had eight points.

SCOREBOARD

In other quarterfinal games Wednesday, the matchups were: Canada-Puerto Rico; China-France, and Australia-Belgium.

UP NEXT

Serbia: Tournament is over.

U.S.: Plays in the semifinals on Friday.