Mavericks forward and Maine native Cooper Flagg runs into defensive pressure from the Celtics' Luka Garza and Sam Hauser in the fourth quarter.
Mavericks forward and Maine native Cooper Flagg runs into defensive pressure from the Celtics' Luka Garza and Sam Hauser in the fourth quarter.Matthew J. Lee/Globe Staff
Jayson Tatum’s return to the Celtics’ lineup,298 days after tearing his right Achilles’ tendon in Game 4 of the Eastern Conference semifinals, was the story across the NBA Friday night, not to mention one of the most intriguing plot developments of the entire season.
But the citizens of one New England state could be forgiven if Tatum’s triumphant return — he finished with 15 points, 12 rebounds, and 7 assists, looking like a slightly rusty version of the Jayson Tatum who has been a first-team All-NBA selection for three straight seasons — was merely a satisfying sidebar to the main story from their perspective.
Or Maine story, as it were. Anticipation for Cooper Flagg’s first NBA game at TD Garden began … oh, sometime in between when he began looking like a future pro while leading Nokomis High School in Newport, Maine, to a state championship as a 15-year-old in 2022, and his continuous ascent since, which includes winning national player of the year as a freshman at Duke last season, and becoming the no-doubt No. 1 pick in the 2025 NBA Draft by the Dallas Mavericks.
The moment arrived last night when Flagg’s Mavericks visited the Garden, their lone visit here during his rookie season.
Flagg, who is from a family of passionate Celtics fans — his mom, Kelly, grew up in a household that had a Larry Bird poster in the kitchen — had never played at the Garden until Friday night.
The outcome had to be close to ideal for the majority of the Garden crowd. The Celtics prevailed, 120-100, but the 19-year-old Flagg acquitted himself well. He shot just 7 of 23, but served the fulcrum of the Mavericks’ offense with 16 points, 8 rebounds, and 6 assists in his second appearance since returning from a foot injury that cost him eight games.
Tatum, of course, received the loudest cheers, just a few decibels below the Payton Pritchard-hits-halfcourt-3-pointer-in-the Finals level, which is about as loud as the Garden can get. But Flagg got a rousing ovation of his own, including a few hoots during the Star-Spangled Banner after the words “our flag was still there.”
“I’ve never heard a road player get a cheer like that in Boston,’’ said Mavericks coach Jason Kidd, who has his own history with Celtics fans. “They tend to go the other way.”
Flagg acknowledged that he tried to take a moment before tipoff to take a deep breath and take in the scene. “It’s a dream come true, being out there on that court,” he said afterward. “It’s really special.”
Kelly Flagg estimated in a text message Friday afternoon that the family had gone to three or four Celtics games while Cooper, his twin brother Ace (a standout freshman at the University of Maine), and older brother Hunter were growing up.
This homecoming had a bit of a twist, though. Two years ago, in January 2024, when Flagg was playing at prep powerhouse Montverde Academy in Florida, the team traveled to Maine for a pair of games so he and Ace could play in front of their home state fans.
This time, Maine came to them. The buzz for Tatum’s return and Flagg’s Garden debut brought a crowd that two different members of the Celtics communications team likened Friday night to a conference finals atmosphere.
Judging by kaleidoscope of blue jerseys in the stands — many Flagg No. 32 Mavs jersey, others from his season at Duke — hundreds of fans made the trek from Maine to Causeway Street, a 3-hour trip from Newport, 3½ if you miss the shortcut at the Gardiner toll.
It was fitting that his first visit as an NBA player to the Garden coincided with Tatum’s return. Flagg attended Tatum’s summer basketball camp in high school, and the Celtics star was a believer in Flagg even before he followed the same path to Duke. “I like how he has an edge about him, a toughness,’’ Tatum told me in 2024. “Special kid, special player.”
Flagg referred to Tatum as a mentor more than once during his postgame press conference. “He’s someone that I idolized and watching him go through [different] levels and watching him at Duke and kind of following in his footsteps, it’s just surreal.”
When the game was over, Tatum and Flagg chatted briefly on the parquet, sharing in a night that won’t soon be forgotten.
“I told him it was incredible what he was able to do and how fast he was able to come back,’’ said Flagg.
He was then asked if he might be a Celtic himself someday.
“I love being a Maverick,’’ he said. “It’s home and I don’t want anything else.”
That was the savvy answer of a 10-year veteran rather than a teenaged rookie. And perhaps it is the whole truth. Dallas is his basketball home now.
But Friday night, those from his real home came to see him in Boston, and it sure did feel like it’s where he belongs.
Jayson Tatum is back: How his Celtics season debut unfolded
The Celtics superstar returned to the lineup against the Mavericks on Friday night, a little less than 10 months after rupturing his Achilles.
Chad Finn can be reached at chad.finn@globe.com.