BOSTON — Larry Bird was one of Cooper Flagg’s biggest basketball influences, someone whose game he first absorbed on DVD. As Flagg, in his rookie season with the Dallas Mavericks, developed from a small-town kid in Maine to a budding NBA star, there was a Boston Celtics player of this era who also helped shape him.
Jayson Tatum, Flagg said, was a player he “modeled” his game after. On Friday, the two of them faced each other for the first time in the NBA.
Tatum made his season debut after missing the past 10 months with a torn Achilles tendon. He looked rusty early and missed the first six shots he attempted, but discovered a rhythm just before halftime on his way to a 15-point, 12-rebound, seven-assist evening.
Flagg fought through left foot soreness and finished with 16 points, eight rebounds and six assists in an emotional night inside TD Garden, which was full of basketball fans from across New England who were there to support Flagg and Tatum.
“It’s incredible,” said Flagg after Dallas’ 120-100 loss to Boston. “There are so many levels to it. (Tatum) is someone I idolized growing up. Watched him go through levels and ranks. Watched him at Duke. Kind of followed in his footsteps. … It’s really special just for me to have this experience tonight.”
Tatum tore his right Achilles in a second-round playoff series against the New York Knicks on May 12, 2025 — hours after the Mavericks miraculously won the NBA draft lottery, which allowed them to select Flagg with the No. 1 pick.
So far in his rookie season, Flagg has delivered on the expectations he came into the league with. Flagg’s jump shot is still a work in progress, but he excels everywhere else. He leads the Mavericks in points, rebounds and assists, is second in steals, and ranks third in blocks.
Flagg’s team, however, is in transition. The Mavericks traded Anthony Davis in February and are headed back to the draft lottery this spring. Friday’s loss was their sixth consecutive defeat — and 16th in 18 games.
“I just think we weren’t organized,” Flagg said. “Part of it is us still learning each other. And part of it was I wasn’t good enough.”
Once the lopsided game was over, Flagg and Tatum met near midcourt and exchanged a hug.
“He just told me to keep going,” Flagg said. “He’s been a mentor for me through my journey from Duke to now. Someone I’ve been able to talk to and get advice from. I told him the same. I told him it’s incredible what he’s able to do and how quickly he was able to come back.”
In high school, Flagg attended Tatum’s JT Elite basketball camp, a gathering of the top 20 freshman and sophomores from around the country. That was the first time Tatum laid eyes on him.
“The first impression I had of Coop was just how hard he played, how he competed,” Tatum said on Jason and Travis Kelce’s “New Heights” podcast. “In high school, it’s rare to see a guy who wants to guard the other team’s best player, block every shot, rebound.”
Flagg received a loud ovation when he was introduced Friday during pregame warmups. Hundreds of basketball fans from Maine made the trip to Boston.
Flagg is from a family of Celtics fans, so playing at TD Garden for the first time was going to be special no matter who was suiting up for the Celtics. But the fact that Tatum returned from a devastating injury in Flagg’s first NBA game in Boston only added another layer to it all.
“I tried to take a moment to take a deep breath and take it all in,” Flagg said. “It’s a dream come true. Just being out there on that court. Competing and playing at a high level. It was really special.”