SPOKANE, Wash. — Kim Mulkey got exactly what she wanted: The LSU women’s basketball coach, impossible to miss in a flowery purple sports coat, worked the referees from the opening tip, encouraging them to catch UCLA star Lauren Betts swinging her elbows or camping out too long in the paint.

As the first quarter neared its end Sunday afternoon, Betts was whistled for her second foul after her right elbow connected with Tigers center Aalyah Del Rosario’s head. The top-seeded Bruins’ all-American center would be relegated to the bench with foul trouble for the rest of the half.

The 6-foot-7 Betts had carried the Bruins to this Spokane Region 1 final, so her extended absence proved pivotal — but not how Mulkey had hoped. UCLA held down the fort as Betts sat for more than 10 minutes, outscoring No. 3 LSU by 10 points in the second quarter. Once Betts returned, the Bruins opened a double-digit lead in the third quarter and held off several spirited LSU rallies to claim a 72-65 victory at Spokane Arena. With the win, UCLA advanced to the Final Four of the NCAA women’s tournament for the first time.

“The game was lost in the second quarter,” Mulkey said. “We didn’t capitalize on Betts being off the floor. Betts did not beat us. We guarded her as tough as we could guard her. We allowed perimeter threes and other people to step up.”

Betts was named the region’s most outstanding player after finishing with 17 points, seven rebounds and six blocks, but her methodical offense around the hoop and diligent paint protection on defense would have been squandered if not for junior guard Gabriela Jaquez and junior forward Timea Gardiner. Jaquez had a team-high 18 points and hit four three-pointers, including a dagger with less than two minutes left set up by a kickout pass from Betts.

“The moment was so big,” Betts said. “I found Gabs, and she stays ready. I was so happy for her — pure joy. I have full confidence in [my teammates]. I was more mad at myself that I got the two fouls. This is what we’re talking about when we say we’re a deep team. They had my back.”

Gardiner came off the bench to make five three-pointers, finishing with 15 points just one game after she went scoreless in a Sweet 16 win over Mississippi on Friday. Her contributions were especially crucial because UCLA’s 38.2 percent shooting was its lowest mark during a win this season.

“[Overcoming Betts’s foul trouble] says a lot about the mental toughness of our team,” UCLA Coach Cori Close said. “Two nights ago, [Gardiner] had one of her hardest nights. It was so uncharacteristic. I texted her: ‘We need you to respond, and we believe in you.’ I was pretty confident she was going to respond in a major way.”

The Bruins’ long and physical defense made life difficult for the Tigers, who managed just eight fast-break points, six bench points and five three-pointers. Aneesah Morrow, LSU’s star forward, was held to 15 points on 7-for-19 shooting, and she suffered a bloody nose during a second-half collision with teammate Sa’Myah Smith.

Close noted that UCLA (34-2) executed two “kills” — her staff’s term for three consecutive defensive stops — in the decisive second quarter. LSU (31-6) scored just 12 points in the period, and junior guard Flau’jae Johnson, who poured in 24 of her game-high 28 points during a second-half flurry, took the blame for the Tigers’ poor execution.

“I didn’t have a good second quarter,” she said. “I feel like I made the team go into a drought. I just tried to come back in the second half, not forcing it, just play within the system and try to make some stuff happen. A lot of my turnovers, I don’t think [UCLA] did anything. I think it was unforced. It was on me.”

For UCLA, the victory provided a measure of revenge after it fell to LSU in the Sweet 16 last year, and it stood as further evidence that it is a team with all the ingredients needed to win the national title. Betts waved goodbye to the Tigers’ bench with both hands after the buzzer sounded, and the Bruins bounced around gleefully after making school history. Two more wins will give UCLA an NCAA championship to go with the Association for Intercollegiate Athletics for Women title that the school claimed in 1978.

“Since we lost [to LSU] a year ago, we’ve remembered that and used it as fuel,” Jaquez said. “We’ve all gotten better and grown from that. I couldn’t be more proud to be a part of this team.”

The Bruins now head to Tampa, where they will face the winner of Spokane’s other region final between top-seeded USC and second-seeded Connecticut. (Those teams meet Monday.) UCLA’s only losses came to USC, defeats that the Bruins avenged in the Big Ten tournament title game. Those three meetings preceded USC star JuJu Watkins’s season-ending knee injury in the second round of this tournament.

A relieved Betts laughed when asked whether she had a rooting interest between the Trojans and Huskies, choosing to play up the Bruins’ growth rather than provide bulletin-board material for their crosstown rivals.

“There were a lot of things we could have gotten down about,” Betts said. “We had fouls, and we had people maybe not getting calls. I think we were all mentally prepared, and we’ve toughened up since midseason. We’ve learned a lot.”