The silence was not total, though. A fan yelled, "We love you Boston!" Another yelled, "We love you KG!" -- a reference to Celtics star Kevin Garnett.
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During the national anthem, a montage of photos related to the marathon bombings was shown on the scoreboard. One that said "Keep on running, Boston" received thunderous applause.
After the anthem, the Knicks were introduced to boos, a sign that things are returning to normal in this city.
The Celtics also honored first responders and others -- what the team called "Heroes Among Us" -- during timeouts and after the first quarter.
Those men and women included politicians, law enforcement, medical personnel and volunteers from the Boston Athletic Association, which runs the Marathon.
The Celtics became the third major Boston sports team to return to action in the city since the bombings.
The Celtics hadn't played a home game since April 10; their April 16 regular-season game was canceled in the aftermath of the bombings.
The Boston Bruins and Red Sox already had hosted games in the wake of the bombings. The Celtics are wearing a patch on their uniforms that reads, "Boston Stands As One."
"Boston Strong" T-shirts also were distributed to fans.