LAS VEGAS -- Even though Southern California was perfect on the season, coach Andy Enfield tried a new lineup Thursday night.
Enfield started four guards against Missouri State because in three of their past four games, the Trojans trailed by double digits in the first half.
This time, they never trailed at all.
Elijah Stewart scored 21 points to lead No. 23 USC past Missouri State 83-75 in the third round of the Las Vegas Classic as the Trojans remained one of six unbeaten teams in Division I.
Southern California (12-0) shot 55 percent from the field and will play Wyoming in the championship game Friday night.
"I just wanted to try something different," Enfield said. "We got out in transition and spread the floor. We played really good defense."
Jordan McLaughlin added 19 points, while Chimezie Metu had 13 points and nine rebounds for the Trojans.
Stewart was 7 of 10 from the field, including 4 of 6 from 3-point range.
"We just aren't selfish," he said. "If it is not your night, you get off of it. I don't mind giving it to a freshman. Whoever is hot, we just feed them."
Alize Johnson and Ronnie Rousseau III led Missouri State (8-4) with 17 points each. Johnson pulled down nine rebounds.
Ryan Kreklow had 12 points and Dequon Miller added 11 as the Bears finished 13 of 35 from 3-point range. The 35 attempts were a school record.
"The last 2 1/2 minutes took about 25 minutes," Enfield said. "But give (Missouri State) credit. They have some good shooters and they made some 3s at the end."
USC outscored the Bears in the paint 38-18.
The Trojans' 19-point second-half lead was cut to 70-63 with 1:23 left, but the Bears got no closer after taking a string of 3-pointers down the stretch.
"They don't make many mistakes," Missouri State coach Paul Lusk said about USC. "Offensively, they can hurt you so many ways. They have a lot of talented offensive players. They're skilled. Jordan McLaughlin plays at his own pace. They made some back-breaking plays."
This was the first meeting between the schools.
BIG PICTURE
USC: The Trojans' winning streak to start the season is their longest since 1971, when they won 16 straight. ... Coming in, the Trojans were seventh nationally in blocks, averaging 7.0 per game. However, USC only had four on Thursday.
Missouri State: This was the Bears' toughest test of the season, facing their first Top 25 opponent. ... It was only the second time Missouri State trailed at halftime this season. ... No Bears player had two field goals until Miller got his second on a 3-pointer with 2:01 left until halftime.
FAST START
USC scored the first six points. After Missouri State answered with the next five, the Trojans went on an 8-0 run and built their largest lead of the half at 39-25.
SIN CITY
This is the fifth time the Trojans have played at the Orleans Arena, either at the Las Vegas Invitational or Classic. USC played here in 2007 and 2012, splitting its two games here each time.
Meanwhile, this is the fourth time the Bears have been in the Las Vegas Classic, making previous appearances in 2001, 2007 and 2011. The Bears are 8-7 in Las Vegas.
UP NEXT
USC plays in the Classic's championship game against Wyoming on Friday night.
Missouri State plays DePaul for the second time this season in the consolation game Friday. The Bears lost 68-66 at DePaul on a buzzer-beating shot Nov. 23.