Antoine Walker contributed 22 points and Paul Pierce added 18 for the Celtics, who built a 17-point second-quarter advantage but allowed the Nets to crawl within 74-72 on a layup by Eddie Gill with 10 1/2 minutes left.
Gill's basket marked the eight millionth point in NBA history.
Walker and Pierce responded by draining 3-pointers around a miss by Mark Strickland to give Boston a five-point lead and New Jersey got no closer than that the rest of the way.
"We missed a lot of close shots, especially towards the end," said New Jersey coach Byron Scott. "It's frustrating to see, but you have to give credit to the Celtics for hitting big shots down the stretch."
The Celtics and Nets might just be playing out the string, but tempers flared on Boston's side as Walker and Pierce were both ejected in the fourth quarter after disputing calls. Coach Jim O'Brien was hit with a technical foul late in the first half.
Keith Van Horn netted 21 points for the Nets but suffered through a 7-of-22 shooting performance. New Jersey, which received 15 points apiece from Lucious Harris and rookie Stephen Jackson, dropped their fifth straight.
McCarty scored 16 of his points in the first quarter and had 21 by the break. His previous career high of 20 points came at Sacramento on February 17, 1998 and his high for that season had been 17.
"They were leaving me open and my teammates were doing a really good job getting me the ball," said McCarty. "Once you get it you just have to hope it goes in. We ran a lot of those plays in practice, especially shooting drills and shooting is something I do really well. It's part of my game."
In a rare start, McCarty played 37 minutes, the second-highest total on the team for the game.
"It felt really good to just get the minutes today," he added. "I feel blessed that I had a chance to go out there and play. I know what I can do as a player. I just have to be patient and accept the coach's decision."
Pierce collected 11 rebounds for Boston, which held a 50-41 advantage on the boards and shot 44 percent (31-of-80) while holding the Nets to 39 percent (31-of-80).
New Jersey held an 18-11 advantage at the foul line but the Celtics were 14-of-31 from 3-point range, including 6-of-12 by McCarty.
"They were leaving us 3-point shooters open all game," said Boston guard Chris Herren.
Walker dished out 12 of Boston's 26 assists.