BOSTON — Former Boston Celtics and current Washington Wizards guard Marcus Smart said a fan “crossed the line” when he was heckling the road team’s bench during Sunday’s game at TD Garden, leading to a bit of shouting before the fan was ushered out of the arena.

“He just crossed the line. We all know, I don’t do line crossing,” Smart said after the Celtics beat the Wizards 124-90. “You never want to see that, especially for a guy who’s coming back and has given the city everything he has.”

The game between the defending NBA champions and a team competing for the worst record in the league was never close, and Boston led by 35 with about six minutes left when a hubbub arose behind Washington’s bench. Smart was pointing at a fan and it appeared his teammates and a coach were trying to hold him back.

Smart said he was pointing the man out to security. “Just trying to get him out before it escalated more than what it was,” he said.

Smart was drafted by the Celtics in 2014 and played the first nine years of his career with the team, but he was traded to Memphis in the summer of 2023 in a deal that brought Kristaps Porzingis to Boston.

The Celtics, who reached the Eastern Conference finals six times with Smart and the NBA Finals once, went on to win it all in the first year without him. Smart did not play in last year’s game when the Grizzlies visited Boston; he did play for Memphis in Boston in December.

Back in the city for the first time since he was traded to Washington in February, Smart did not play on Sunday as the Wizards focus on young players and the draft lottery. During the game, fans chanted: “We want Marcus!”

“Flashbacks, baby,” Smart said. “The love is always there. From both sides — myself and the fans, the city. It’s definitely emotional coming back and you try to hold it back. But I love it. I love every last bit of it. I’m a part of the city — nine years. A kid to a young man.”

Smart spent a long time after the game catching up with his former teammates.

“It’s always good to keep in touch with those guys,” he said. “Grew up with those guys. We went through a lot of battles — blood, sweat and tears. A few of those guys came to my mom funeral. So it’s a deeper bond than just basketball between us.”

In Washington, the club is sure glad to have him on its side. In fact, a Boston reporter on Sunday asked Wizards coach Brian Keefe about Smart’s leadership in a young locker room, with him summing it up succinctly, as “he’s been terrific.

“We’re thrilled to have him on our team,” he added. “Obviously, you guys know here in this town, what he meant to the city of Boston. He’s a tremendous leader, a tremendous player.”

The Associated Press contributed to this report.