Both of the forwards finished with double-doubles as the Celtics ended a four-game losing streak with victory at Boston's TD Garden.
"I just thought we played together, we didn't really worry about shots," Sullinger told reporters after the game.
"We created for one another, we moved the ball really quickly. Rondo played a lot like himself and had to cue on that so. We just played our game."
The win sees the Celtics sitting in fourth position in the Atlantic Division with a record of 16-33.