Suns forward Mikal Bridges drives on Celtics center Robert Williams III during the Suns’ 111-90 win on Friday in Phoenix. Rick Scuteri/Associated Press

PHOENIX — JaVale McGee had season highs with 21 points and 15 rebounds, Chris Paul added 12 assists and the Phoenix Suns rolled to a 111-90 win over the Boston Celtics on Friday night.

The Suns won for the 20th time in 21 games despite missing starters Devin Booker (hamstring) and Deandre Ayton (non-COVID illness). Booker has missed four games in a row while Ayton was a late scratch because he didn’t feel well at the morning shootaround.

McGee picked up the slack, shooting 9 of 16 from the field and even knocking down a 3-pointer, which was just the 11th in his 14-year career. The 7-footer was one of Phoenix’s biggest pickups during free agency, and he’s been very good so far in the desert.

The veteran is on pace to average more than 10 points per game for just the fourth time.

Seven Suns scored in double figures. Cam Payne had 17 points while Jae Crowder and Cameron Johnson both added 16.

The Celtics have lost three straight and fell to 13-14. This one was particularly rough.

Boston’s offense looked disjointed all night, and nobody could shoot. Jayson Tatum led the Celtics with 24 points but shot just 10 of 25 from the field. Marcus Smart was 1 of 13. The entire team was 4 of 26 (15%) from 3-point range.

Phoenix took an 84-69 lead after the third quarter and pushed that advantage to 20 points by early in the fourth to cruise to the win.

Both teams were missing important players — Boston was without Jaylen Brown (hamstring) and Josh Richardson (COVID-19 protocol) — but the Suns didn’t look bothered by the absences while the Celtics appeared lost.

McGee scored 11 points while Landry Shamet and Mikal Bridges both added 10 as Phoenix used a 25-3 run to take a 57-39 lead at the break. The Celtics had just five assists in the first half and shot 1 of 12 from 3-point range.

JALEN’S CHANCE

Suns second-year forward Jalen Smith got the rare chance for extended playing time since Ayton wasn’t in the lineup. The 6-foot-10 backup finished with seven points and nine rebounds.

The No. 10 overall pick in the 2020 draft has had a disappointing start to his career and barely played during the team’s run to the NBA Finals last season.

He’s still painfully awkward at times but did have some good moments Friday. He made a 3-pointer and threw down a powerful dunk after a smooth pass from Paul. He also added a steal and two blocks.

TIP-INS

Celtics: Brown, Richardson and C Bruno Fernando (back spasms) didn’t play. … Smart missed his first 11 shots before hitting his 12th late in the third quarter.

Suns: Ayton missed his seventh game of the season. He joined Booker, F Abdel Nader (knee) and F/C Frank Kaminsky (knee) on the injured list. … The feisty Suns picked up three technical fouls — one each for Bridges, Paul and Crowder.