Robinson took the floor after Rondo was held out of the contest due to a tight hamstring, and he responded with a big game, going 8-of-12 from the field, grabbing six rebounds and handing out six assists for the Celtics, who won their seventh straight game.
Marquis Daniels hit a pair of free throws with 7 minutes left in the first half to put Boston up 34-27 and his subsequent lay-in off a Nets turnover ignited an 18-4 run, capped by Garnett's 4-foot jumper with 1:06 left.
Garnett contributed 13 points and 14 rebounds and Glen Davis chipped in 16 points and nine boards in a reserve role for the victors.
New Jersey was led by Jordan Farmar with 16 points.
Derrick Favors and Anthony Morrow donated 10 apiece for the Nets.