For the first time in 210 days, the Celtics were able to trot out their preferred starting five Monday night at TD Garden.

The result: a hero’s welcome for the now-healthy Kristaps Porzingis and a comprehensive beatdown of one of the NBA’s hottest teams.

Boston steamrolled the Los Angeles Clippers 126-94 in Porzingis’ return from offseason leg surgery.

Porzingis played 22 minutes in his season debut, showing some expected signs of rust but finishing with 16 points, six rebounds, two assists, two blocks and one steal. Jayson Tatum led all Boston starters with 20 points on 7-of-15 shooting. Derrick White added 19 points, seven assists, four rebounds and a steal, and Jaylen Brown scored 17, plus six boards, four assists, three steals and one block.

White (5-for-9) and bench scorers Payton Pritchard (6-for-10) and Sam Hauser (3-for-3) led another explosive 3-point effort for the Celtics, who went 22-for-51 (43.1%) from downtown in the win. Pritchard scored 20 points and grabbed two steals as his NBA Sixth Man of the Year campaign continued.

The Kawhi Leonard-less Clippers, owners of the league’s fourth-best defensive rating, came in riding a five-game win streak, during which they allowed just 96.8 points per game. The Celtics surpassed that mark before the end of the third quarter.

Porzingis, who missed Boston’s first 17 games, waited until 10 minutes into warmups to take the court, doing so with a smile on his face and a paper coffee cup in his right hand. His solo entrance preceded a personalized hype video that played on the Garden Jumbotron, its final shot an all-caps declaration: “HE’S BACK.”

The fan-favorite big man remained the center of attention once the game tipped off. Porzingis attempted 3-pointers on three of the Celtics’ four possessions and four of their first seven. Though he made just one of those — after his third miss, he grinned, seemingly acknowledging the impact of his long layoff — he was immediately impactful on the defensive end.

Before being subbed out for Neemias Queta seven minutes in, Porzingis helped force misses by Ivica Zubac, Amir Coffey and Derrick Jones Jr. with strong contests at the rim.

Rim protection was one of Boston’s biggest areas of concern in Porzingis’ absence — they dropped from fifth-best last season to eighth-worst this season in opponent shooting percentage inside the restricted area and first to 14th in blocks per game — so this had to be a welcome sight for Joe Mazzulla and Co.

Queta, a healthy DNP in Sunday’s win over Minnesota, blocked two shots in the first quarter, including one by James Harden. He had some difficulties against Zubac, who was LA’s only consistent scorer in the game (23 points on 11-of-14 shooting, 10 rebounds), but was a solid second option with Al Horford (illness/rest) and Luke Kornet (hamstring) both unavailable.

The Celtics led 27-20 after one quarter, then stretched their lead to 29 points in the second by doing what they do best: flooding their opponent beneath a tsunami of threes. They went 12-for-17 from deep during a merciless 51-point quarter — the third-highest-scoring quarter in franchise history and highest since 1970. White hit four triples on his own. Brown and Pritchard made three apiece. Sam Hauser and Holiday each had one.

The 12 made threes tied the NBA record for a single quarter. It also equaled the total number of threes the Clippers attempted in the entire first half. Boston led 78-49 at halftime.

Porzingis did not have a hand in that second-quarter 3-point parade, but impacted the game in several other areas. He threw down an acrobatic dunk off a Brown alley-oop, scored on a put-back after a Brown miss, assisted on two made threes, notched one steal and recorded one official block, plus another as the Clippers’ shot clock expired to force a 24-second violation.

The Celtics went cold to start the third quarter, surrendering a 10-0 Clippers run that spanned more than 4 1/2 minutes. Tatum ended Boston’s scoring drought with a dunk, then Porzingis went to work, manipulating post-ups to score six straight Celtics points across four possessions.

A flurry of threes from Pritchard (two) and Hauser (one) gave Boston some additional breathing room, and despite scoring just 21 points in the frame, it took a 21-point lead into the fourth quarter.

The Celtics cruised from there, with the Garden crowd reaching max volume after Pritchard slipped past a Clippers defender and lofted a lob to Porzingis, who slammed it home.

Joe Mazzulla emptied his bench midway through the fourth, giving late minutes to the seldom-used Jaden Springer and Baylor Scheierman. Queta was a force in garbage time, finishing with 12 points on 5-of-6 shooting, nine rebounds, four blocks and two steals.

The Celtics are off until Friday, when they visit the Chicago Bulls in their final game of NBA Cup group play.