Maine’s Cooper Flagg plays first NBA game in Boston: Full breakdown

Maine basketball phenom Cooper Flagg played his first NBA game in Boston, as the Celtics defeated Flagg and the Dallas Mavericks 120-100 on Friday.Flagg, 19, faced his favorite childhood team at TD Garden, the NBA arena that is closest to his hometown of Newport. “I tried to take a moment to take a deep breath and take it all in,” Flagg said after the game. “It’s a dream come true being out there on that court, competing and playing at a high level, is really special.”Friday’s game also marked the season debut of Celtics star Jayson Tatum, who has been working to return from a ruptured Achilles tendon he suffered in May 2025 during the NBA Playoffs. The Celtics announced earlier on Friday that Tatum was available to play against the Mavericks.Flagg scored 16 points on 7 of 23 shooting and finished with eight rebounds, six assists and one steal in 30 minutes. This was the second night of a back-to-back for Flagg, who had missed eight straight games with a sprained foot before playing against the Orlando Magic on Thursday.Tatum started the game and scored 15 points on 6 of 16 shooting while adding 12 rebounds, seven assists and one steal in 27 minutes.WMTW sports director Travis Lee was at TD Garden for the big game and Maine’s Total Coverage ran a live blog, which also covered what happened pregame.4th Quarter 9:21 p.m. – The game ends in a 120-100 Celtics victory. Flagg and Tatum, both Duke alumni, embraced after the final buzzer.9:15 p.m. – Flagg heads to the bench with 4:20 to play and the Mavericks trailing 113-90. He played 30 minutes and scored 16 points on 7 of 23 shooting. Flagg also recorded eight rebounds, six assists and one steal.9:14 p.m. – Tatum receives a loud ovation from the TD Garden crowd as he heads to the bench with 5:01 remaining and the Celtics holding a 112-87 lead. He had 15 points, 12 rebounds, seven assists and a steal in 27 minutes upon leaving the game.9:08 p.m. – The Mavericks take another timeout after a Tatum 3-pointer gives the Celtics a 106-87 lead with 6:47 to go. Tatum has 15 points, 10 rebounds, six assists and a steal in his season debut.9:02 p.m. – Flagg makes a floater to pull the Mavs back within 12 points, as the Celtics lead 99-87 with 8:41 remaining in the game. Flagg has 16 points, seven rebounds, five assists and one steal in 26 minutes. 8:57 p.m. – The Mavericks call a timeout after the Celtics take a 94-82 lead with 10:41 to play.8:55 p.m. – Flagg reenters the game at the start of the fourth quarter and makes a driving layup. He now has 14 points.3rd Quarter8:52 p.m. – The third quarter ends with the Celtics holding a 90-80 lead. Flagg remained on the bench for the final 4:43 of the quarter.8:40 p.m. – Flagg checks out of the game with 4:43 left in the quarter and the Celtics leading 76-72. He has 12 points, five rebounds, five assists and one steal in 22 minutes.8:33 p.m. – The Mavericks take a timeout with 7:22 remaining in the quarter after the Celtics take a 72-64 lead behind a 12-3 run.8:27 p.m. – Flagg starts the third quarter on the floor and makes his first shot attempt of the second half, giving him 12 points.2nd Quarter8:10 p.m. – The first half ends with the Celtics leading 58-53. Tatum scored his first points of the game on a dunk with 1:13 remaining in the second quarter. Flagg answered with a floater to get to 10 points, but Tatum responded with a 3-pointer and Derrick White made a dunk through a foul.8:01 p.m. – The Mavericks take a timeout with 2:40 to go before the break after Flagg committed a foul on Jaylen Brown, who made the shot through contact. Dallas leads 48-46 and Flagg has eight points, two rebounds and one steal in 12 minutes played.7:56 p.m. – Flagg makes his third field goal of the game, giving the Mavericks a 43-40 lead with 4:31 left until halftime.7:52 p.m. – Flagg checks back into the game after teammate Dwight Powell made the first of two free throws. Powell would make the second to tie the game 31-31 with 7:29 remaining in the quarter.7:51 p.m. – Flagg was still on the bench coming out of the timeout, but he was seen heading to the scorer’s table to check into the game.7:47 p.m. – The Celtics take a timeout with 8:59 remaining in the quarter, shortly after Tatum was unable to finish off a dunk attempt. The Mavericks lead 29-26.7:45 p.m. – The Celtics announced that Nikola Vucevic, whom they acquired before the trade deadline, fractured his right ring finger and was ruled out for the rest of the game.7:42 p.m. – Flagg starts the second quarter on the Mavericks’ bench, while Tatum returned to the floor for the Celtics.1st Quarter7:38 p.m. – The Celtics take a 23-22 lead at the end of the first quarter on a buzzer-beating tip-in by Payton Pritchard. Flagg spent the last 4:21 of the quarter on the bench.7:31 p.m. – Flagg is taking a breather on the bench coming out of the timeout.7:27 p.m. – The Celtics take a timeout after the Mavericks take a 13-12 lead with 4:21 left in the first quarter. Flagg has six points, one rebound and one steal at this point in the game.7:26 p.m. – Flagg scores on the fastbreak to make it 12-11 Celtics with 4:57 remaining in the quarter.7:21 p.m. – Flagg is seen trying to keep his left foot loose as he heads to the free-throw line. He made both at the line.7:17 p.m. – Flagg gets fouled driving to the basket and came up limping. He tried to walk it off, but the Mavericks decided to call a timeout before he attempted a free throw.7:16 p.m. – Flagg scores his first basket of the game, tying the game 2-2 with 8:57 remaining in the first quarter. He has mostly been guarding Tatum in the early going.Pregame Cooper Flagg gets some love from the fans at TD Garden during the starting lineup announcements. Watch in the embedded social media video below.6:45 p.m. – Jayson Tatum is announced as part of the Celtics’ starting lineup in his first game back from a ruptured Achilles he suffered in the 2025 NBA Playoffs. Derrick White, Jaylen Brown, Sam Hauser and Neemias Queta round out Boston’s starting five.6:42 p.m. – Cooper Flagg is announced as part of the Mavericks’ starting lineup, along with Max Christie, Khris Middleton, P.J. Washington and Dwight Powell.6:37 p.m. – The Mavericks shared photos of Cooper Flagg fans who are attending the game.6:32 p.m. – The Mavericks shared a photo and video of Flagg’s teammate, Naji Marshall, warming up in an “In Flagg We Trust” T-shirt.6:26 p.m. – The Mavericks shared a video of Cooper Flagg fans in the stands at TD Garden.6:12 p.m. – The Mavericks shared photos of their players arriving at TD Garden, including Cooper Flagg.5:45 p.m. – WMTW sports director Travis Lee recorded video of warmups from up in the balcony and he spotted Jayson Tatum on the floor with his teammates. Watch in the embedded social media video below.4:55 p.m. – Maine’s Total Coverage recorded video of Cooper Flagg warming up for the game. Watch it in the embedded video player below.

BOSTON —

Maine basketball phenom Cooper Flagg played his first NBA game in Boston, as the Celtics defeated Flagg and the Dallas Mavericks 120-100 on Friday.

Flagg, 19, faced his favorite childhood team at TD Garden, the NBA arena that is closest to his hometown of Newport.

“I tried to take a moment to take a deep breath and take it all in,” Flagg said after the game. “It’s a dream come true being out there on that court, competing and playing at a high level, is really special.”

Friday’s game also marked the season debut of Celtics star Jayson Tatum, who has been working to return from a ruptured Achilles tendon he suffered in May 2025 during the NBA Playoffs. The Celtics announced earlier on Friday that Tatum was available to play against the Mavericks.

Flagg scored 16 points on 7 of 23 shooting and finished with eight rebounds, six assists and one steal in 30 minutes. This was the second night of a back-to-back for Flagg, who had missed eight straight games with a sprained foot before playing against the Orlando Magic on Thursday.

Tatum started the game and scored 15 points on 6 of 16 shooting while adding 12 rebounds, seven assists and one steal in 27 minutes.

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WMTW sports director Travis Lee was at TD Garden for the big game and Maine’s Total Coverage ran a live blog, which also covered what happened pregame.

4th Quarter

9:21 p.m. – The game ends in a 120-100 Celtics victory. Flagg and Tatum, both Duke alumni, embraced after the final buzzer.

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Cooper 🤝 JT

Two guys from Duke.
One grew up watching the other on the Celtics.

Tonight, they battled for the first time against each other in the NBA. pic.twitter.com/dNjXaZwQFN

— NBA (@NBA) March 7, 2026

9:15 p.m. – Flagg heads to the bench with 4:20 to play and the Mavericks trailing 113-90. He played 30 minutes and scored 16 points on 7 of 23 shooting. Flagg also recorded eight rebounds, six assists and one steal.

9:14 p.m. – Tatum receives a loud ovation from the TD Garden crowd as he heads to the bench with 5:01 remaining and the Celtics holding a 112-87 lead. He had 15 points, 12 rebounds, seven assists and a steal in 27 minutes upon leaving the game.

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9:08 p.m. – The Mavericks take another timeout after a Tatum 3-pointer gives the Celtics a 106-87 lead with 6:47 to go. Tatum has 15 points, 10 rebounds, six assists and a steal in his season debut.

9:02 p.m. – Flagg makes a floater to pull the Mavs back within 12 points, as the Celtics lead 99-87 with 8:41 remaining in the game. Flagg has 16 points, seven rebounds, five assists and one steal in 26 minutes.

8:57 p.m. – The Mavericks call a timeout after the Celtics take a 94-82 lead with 10:41 to play.

8:55 p.m. – Flagg reenters the game at the start of the fourth quarter and makes a driving layup. He now has 14 points.

3rd Quarter

8:52 p.m. – The third quarter ends with the Celtics holding a 90-80 lead. Flagg remained on the bench for the final 4:43 of the quarter.

8:40 p.m. – Flagg checks out of the game with 4:43 left in the quarter and the Celtics leading 76-72. He has 12 points, five rebounds, five assists and one steal in 22 minutes.

8:33 p.m. – The Mavericks take a timeout with 7:22 remaining in the quarter after the Celtics take a 72-64 lead behind a 12-3 run.

8:27 p.m. – Flagg starts the third quarter on the floor and makes his first shot attempt of the second half, giving him 12 points.

2nd Quarter

8:10 p.m. – The first half ends with the Celtics leading 58-53. Tatum scored his first points of the game on a dunk with 1:13 remaining in the second quarter. Flagg answered with a floater to get to 10 points, but Tatum responded with a 3-pointer and Derrick White made a dunk through a foul.

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8:01 p.m. – The Mavericks take a timeout with 2:40 to go before the break after Flagg committed a foul on Jaylen Brown, who made the shot through contact. Dallas leads 48-46 and Flagg has eight points, two rebounds and one steal in 12 minutes played.

7:56 p.m. – Flagg makes his third field goal of the game, giving the Mavericks a 43-40 lead with 4:31 left until halftime.

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7:52 p.m. – Flagg checks back into the game after teammate Dwight Powell made the first of two free throws. Powell would make the second to tie the game 31-31 with 7:29 remaining in the quarter.

7:51 p.m. – Flagg was still on the bench coming out of the timeout, but he was seen heading to the scorer’s table to check into the game.

7:47 p.m. – The Celtics take a timeout with 8:59 remaining in the quarter, shortly after Tatum was unable to finish off a dunk attempt. The Mavericks lead 29-26.

7:45 p.m. – The Celtics announced that Nikola Vucevic, whom they acquired before the trade deadline, fractured his right ring finger and was ruled out for the rest of the game.

7:42 p.m. – Flagg starts the second quarter on the Mavericks’ bench, while Tatum returned to the floor for the Celtics.

1st Quarter

7:38 p.m. – The Celtics take a 23-22 lead at the end of the first quarter on a buzzer-beating tip-in by Payton Pritchard. Flagg spent the last 4:21 of the quarter on the bench.

7:31 p.m. – Flagg is taking a breather on the bench coming out of the timeout.

7:27 p.m. – The Celtics take a timeout after the Mavericks take a 13-12 lead with 4:21 left in the first quarter. Flagg has six points, one rebound and one steal at this point in the game.

7:26 p.m. – Flagg scores on the fastbreak to make it 12-11 Celtics with 4:57 remaining in the quarter.

7:21 p.m. – Flagg is seen trying to keep his left foot loose as he heads to the free-throw line. He made both at the line.

7:17 p.m. – Flagg gets fouled driving to the basket and came up limping. He tried to walk it off, but the Mavericks decided to call a timeout before he attempted a free throw.

7:16 p.m. – Flagg scores his first basket of the game, tying the game 2-2 with 8:57 remaining in the first quarter. He has mostly been guarding Tatum in the early going.

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Pregame

Cooper Flagg gets some love from the fans at TD Garden during the starting lineup announcements. Watch in the embedded social media video below.

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6:45 p.m. – Jayson Tatum is announced as part of the Celtics’ starting lineup in his first game back from a ruptured Achilles he suffered in the 2025 NBA Playoffs. Derrick White, Jaylen Brown, Sam Hauser and Neemias Queta round out Boston’s starting five.

6:42 p.m. – Cooper Flagg is announced as part of the Mavericks’ starting lineup, along with Max Christie, Khris Middleton, P.J. Washington and Dwight Powell.

6:37 p.m. – The Mavericks shared photos of Cooper Flagg fans who are attending the game.

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6:32 p.m. – The Mavericks shared a photo and video of Flagg’s teammate, Naji Marshall, warming up in an “In Flagg We Trust” T-shirt.

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6:26 p.m. – The Mavericks shared a video of Cooper Flagg fans in the stands at TD Garden.

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6:12 p.m. – The Mavericks shared photos of their players arriving at TD Garden, including Cooper Flagg.

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5:45 p.m. – WMTW sports director Travis Lee recorded video of warmups from up in the balcony and he spotted Jayson Tatum on the floor with his teammates. Watch in the embedded social media video below.

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4:55 p.m. – Maine’s Total Coverage recorded video of Cooper Flagg warming up for the game. Watch it in the embedded video player below.