The Red Bulls were on top throughout the match, thanks largely to Thierry Henry, and the scoreline could have been even wider.
Eric Alexander wasted the game's first half-chance, smashing over from the edge of the penalty area, but made up for it moments later when he fired past the goalkeeper after Henry had found him on the right of the box.
They doubled their lead just five minutes later, with Henry getting on the scoresheet himself, finishing well from Fabian Espindola's cross.
The hosts continued to push forward and almost went further in front around the half-hour mark when Alexander was found in space once again just inside the box; this time, though, he smashed his effort against the crossbar.
At the beginning of the second half, Montreal finally threatened at the other end. First Justin Mapp was denied by Luis Robles in goal and then Marco Di Vaio was thwarted by the goalkeeper from the edge of the box.
They were made to pay shortly after when Tim Cahill met Henry's corner and headed the ball into the top corner.
Cahill almost got his second in identical circumstances towards the end of the game, but he headed against the bar.
That was the final action of the game and it was Red Bulls who took the points as well as the lead in the Eastern Conference.