Breanna Stewart of the United States drives to the basket against Australia during a women’s basketball Olympic quarterfinal Wednesday in Saitama, Japan. AP Photo/Eric Gay

SAITAMA, Japan — Breanna Stewart and the U.S. women played their best basketball of the Tokyo Games, putting on a dominant performance that team has been known for over the years en route to winning six consecutive Olympic gold medals.

The Seattle Storm star was a big reason why the Americans were so impressive, scoring 20 of her 23 points in the first half as the U.S. routed the Aussies 79-55 Wednesday in the quarterfinals.

“We wanted to come out and set the tone on both ends of the floor,” Stewart said. “We haven’t had great starts to the games so far. This is the quarterfinals and it’s win or go home.”

The Americans will face Serbia on Friday in the semifinals looking to advance to their seventh consecutive gold medal game. The Serbians, who won the bronze medal in the 2016 Rio Games, rallied to beat China 77-70 in the quarterfinals.

In another quarterfinal, Marine Johannes scored 18 points and Gabby Williams hit key free throws late to help France edge Spain 67-64 on Wednesday night. The French team will face host Japan in the semifinals on Friday in a rematch of a group play game that they lost by four. Saki Hayashi hit a 3-pointer with 15.2 seconds left to lift Japan over Belgium 86-85 on Wednesday.

For the first time since getting together about three weeks ago the U.S. looked like the team that’s won 53 consecutive games in the Olympics dating back to the 1992 Barcelona Games.

“Knockout rounds brings out a certain intensity about a team and that played a huge role in it,” said Sue Bird, who had nine points and five assists. “It’s do or die at this point. That helps. I do think we subtly have been taking steps in the right direction and getting better. We’re trending in the right direction and getting more comfortable.”.

During the pool games the U.S. got off to slow starts, trailing after the first quarter in each contest. Stewart made sure that wouldn’t happen against Australia. Trailing 5-2, she scored seven consecutive points to start a 19-1 run. The Americans led 26-12 after the opening quarter as Australia had 10 turnovers in the period.

“The way she did it inside-outside, she was unconscious,” U.S. coach Dawn Staley said. “She took great shots and was efficient. We knew Stewie can score, but it was her defensive effort. She chased those guards around, something she doesn’t do a whole lot. Deflections, blocked shots, made plays. super proud of the all around effort she gave us.”

Australia was able to get within nine in the second quarter before the U.S. closed the half with a 20-8 run to go up 48-27.

The Opals never threatened in the second half as the lead ballooned behind Brittney Griner, who scored 10 of her 15 points in the third quarter.

The U.S. and Australia are ranked No. 1 and 2 in the world and usually meet later in the Olympics, but the Aussies barely qualified for the quarters. They needed at least a 24-point victory over Puerto Rico in the last game of pool play to advance.

The Opals have never beaten the U.S. in the Olympics, losing to the Americans in the gold medal game in 2000, 04 and 08. The Australians also lost in the semifinals of the 1996 and 2012 Olympics to the U.S.

They were looking for a different outcome in Japan. The teams played in Las Vegas last month in an exhibition game and Australia pulled off the upset victory. But the Americans wanted to ensure what happened in Vegas, stayed in Vegas.

“Haven’t had one of these in awhile,” Diana Taurasi, who didn’t play in that game as she was recovering from a hip injury, said of the comfortable win.

Leilani Mitchell scored 14 points to lead Australia, which played without center Liz Cambage and will host the World Championship next year in Sydney. The 6-foot-8 Cambage abruptly left the team before training camp, citing mental health issues.

“I think we can improve a lot,” Australia coach Sandy Brondello said.

FIVE-TIME CLUB

Stewart said she had talked at practice about playing in five Olympics like Taurasi and Bird have. She’s competing in her second in Tokyo. She thinks she has one advantage over the two vets who are 39 and 40.

“If I’m a five-time Olympian I’ll be 37,” she said. “I’m younger than the two of them so it’s possible.”

GIVING IT A TRY

Australia’s Stephanie Talbot, who is on the WNBA’s Seattle Storm. played after missing the team’s last game against Puerto Rico. She only played a few minutes against China after missing the opener against Belgium because of an injured foot. She tested it out before the U.S. game and played 16 minutes, scoring four points.

CHEERING SECTION

The Australia men’s team will face the U.S. men in the semifinals on Thursday. Most of the American men’s team arrived just before the half to watch the women’s team play.