Deandre Ayton scored 25 points, Devin Booker added 23 and the top-seeded Phoenix Suns rolled to a 121-114 win over the Dallas Mavericks on Monday night in Game 1 of the Western Conference semifinals.

The Suns never trailed, jumping to a 9-0 lead in the opening minutes and rarely let off the gas. They shot 50.5% from the field, won the rebounding edge 51-36 and beat the Mavericks for the 10th straight time, counting regular season games.

Luka Doncic led the Mavericks with 45 points, 12 rebounds and eight assists. It’s the first time Dallas has advanced to the postseason’s second round in Doncic’s four-year NBA career.

Doncic and Maxi Kleber looked ready for the challenge but the rest of the Mavs didn’t do much until it was too late. Kleber finished with 19 points.

Game 2 is on Wednesday in Phoenix.

Booker missed three games during Phoenix’s first-round win over the New Orleans Pelicans because of a strained right hamstring suffered in Game 2. He returned for the closeout Game 6 and scored 13 points, but looked a little more cautious than usual in his effort to stay healthy.

That hesitancy was gone in the first quarter on Monday: Booker scored 13 points on 4 of 8 shooting and added six rebounds and four assists.

Ayton dominated in the paint and mid-range, hitting his usual array of turnaround jumpers, runners and dunks. The 6-foot-11 center shot 12 of 20 from the field. Chris Paul added 19 points and Cam Johnson had 17 off the bench.

All five Suns starters scored in double figures.

The Suns’ opening salvo was highlighted by a Jae Crowder 3-pointer and Booker’s lob pass to Mikal Bridges for a dunk. Phoenix extended its lead to 18-6 midway through the first quarter before a discombobulated Dallas called timeout.

The Mavericks stayed in the game for a while thanks to Doncic and Kleber, who hit his first four 3-pointers. The pair helped Dallas pull within 51-47 midway through the second but the Suns finished the half with another run, going into the break with a 69-56 lead.

OUCH

Doncic was slow to get up in the second quarter after taking a knee to the groin from Jae Crowder, who was shooting a 3-pointer and called for the offensive foul.

After an official review, Crowder’s foul was upgraded to a Flagrant 1.

7-FOOT FUN

Suns backup center JaVale McGee brought the crowd to its feet early in the fourth quarter with a rare defensive play on the perimeter.

He stole the ball from Doncic and then dribbled the length of the floor, finishing with a powerful dunk to put the Suns up 21 points.

TIP-INS

Mavericks: Doncic scored 14 points in the first quarter on 5 of 9 shooting. ... Kleber hit 5 of 6 3-pointers in the first half and had 16 points before the break. ... Kleber took a scary fall in the fourth quarter after being bumped by JaVale McGee while finishing a dunk. Kleber landed on his upper back and was shaken up for a few seconds before taking his free throw.

Suns: Crowder hit a 3-pointer in the second quarter then turned and started celebrating with former Cardinals receiver Larry Fitzgerald, who was sitting courtside. Fitzgerald is a part-owner of the franchise. ... It was the 30th consecutive sellout at the Footprint Center, dating back to the regular season. ... Improved to 51-0 this season when leading after three quarters, including a 4-0 mark in the playoffs.