The Las Vegas Aces were well-rested. The Phoenix Mercury were coming off two emotional single-elimination wins.

And in a sea of stars, a bench player stepped into the semifinal spotlight.

Kelsey Plum continuously attacked the basket and scored 25 points as the second-seeded Aces took a 96-90 win over the No. 5 Mercury on Thursday night in Las Vegas. The Aces lead the best-of-five semifinal series 1-0.

"I wanna play, man. I wanna play, I wanna play another game right now," Plum said on the postgame ESPN broadcast. "I'm just, I love basketball. I love basketball. I wanna get in there and compete offense, defense, transition, doesn't matter. I'm guarding my favorite player. I grew up watching Diana [Taurasi] so for me to play in this series, man, it's just so fun."

It wasn't just Plum who showed out in front of a crowd that included Las Vegas Raiders players, Aces and Raiders owner Mark Davis, Utah Jazz players (in town for training camp) and Jazz minority owner Dwyane Wade.

Riquna Williams was nearly the entire offense for the Aces in the first quarter as Las Vegas needed to shake off its rust. She scored 14 of Las Vegas’ 21 points in the period and finished with a game-high 26 points, including four 3-pointers.

Las Vegas took a 52-49 lead into halftime.

Diana Taurasi hobbled in second half

Diana Taurasi, who missed all three games against the Aces in the regular season, was shaken up late in the third quarter after getting caught up and tripping over Dearica Hamby’s leg. In the fourth quarter, she appeared to be in pain after a 3-point attempt. She hopped down the court for the next play but was quickly subbed out. She later returned and finished with 20 points, six assists and five rebounds.

Taurasi played 31 minutes after a 33-minute outing on Sunday in the Mercury’s second-round overtime win over the Seattle Storm.

As Taurasi struggled through injury, the Mercury also lost momentum after pulling out two thrilling single-elimination wins in the first two rounds of the playoffs. While the Big 3 tried to save their legs, the bench struggled to keep pace with the rested Aces in the third quarter.

The Aces reeled off a 12-4 run to end the third and take a 10-point lead into the final period. Plum scored 12 points in the third.

The Aces’ Chelsea Gray posted a double-double with 17 points and 12 assists. A'ja Wilson added 15 points. Las Vegas shot 49.3% from the field and 47.4% from deep.

The Mercury’s Big 3 of Taurasi (20), Brittney Griner (24) and Skylar Diggins-Smith (10) scored 54 of Phoenix’s 90 points. Brianna Turner added 12, and Kia Nurse had 13 as all five starters scored in double figures.

Phoenix shot 47.9% from the field.

Aces center Liz Cambage returned after playing fewer than 10 minutes off the bench in the regular-season finale. Cambage missed the last three weeks of the season after testing positive for COVID-19 despite being fully vaccinated.

The post battles between 6-foot-8 Cambage and 6-9 Griner had flashes of brilliance, but Cambage ran into foul trouble and her minutes were limited to 10.

Game 2 is 10 p.m. ET Thursday on ESPN2 in Las Vegas.