Larry Bird scored 38 points, including three free throws in the final minutes, as Boston held off a late rally by host New Jersey.
Scoring 14 points in the second period and 15 in the third, Bird had 35 points entering the fourth quarter, with the Celtics leading, 80-69. He took only one shot in the final period and finished 15 for 20 from the field. He also had 12 rebounds and six assists.
"When you're not having a great night, a superstar can carry you sometimes," said Boston Coach Bill Fitch, whose team was outrebounded, 48-31. "For a 10-minute period late in the first quarter and early in the second, Larry Bird really carried us."
The Celtics led, 89-75, five minutes into the fourth quarter, but the Nets cut the lead to 92-90 with 2:23 left.
Two free throws by Bird made it 98-91 with 51 seconds to go, but the Nets came back on two three-point goals by Darwin Cook and one by Albert King (29 points) to cut the deficit to 101-100 with seven seconds left.
After Bird made one of two free throws with four seconds left, the Nets' Darryl Dawkins couldn't throw the ball inbounds and Boston held on for the victory.