In their first group stage match of the campaign, goals from Saer Sene and Lloyd Sam were enough to give Red Bulls three points on home soil.
New York dominated the opening exchanges and were rewarded with a break-through on 11 minutes with a well-worked team goal, to the delight of the home fans.
Lurking at the back post Cahill leaped highest and cushioned a cross from the left wing to unselfishly play in teammate Sene, who had enough time to easily poke home from close range.
Cahill nearly got on the scoresheet himself on the half-hour mark when the ball dropped to him in the box but he had his shot blocked from point-blank range.
Red Bulls doubled their advantage in the second-half and were rarely troubled throughout the contest despite spurning several opportunities.
The win moved Red Bulls to second place in Group 3, three points behind leaders Montreal Impact with a game in hand.