The former Everton star produced a neat finish on his left foot from Roy Miller's low cross from the left in the 39th minute before he headed home an 89th-minute winner at the back post from Thierry Henry's stand-up ball from near the byline after Jonathan Osorio's equaliser with seven minutes left.
The victory put the Red Bulls third on the Eastern Conference table and Australian international Cahill was well aware of the importance of the triumph.
"I think the main thing for us is we've dropped a lot of points on the road and we've played such bad football and today I thought especially in the first half we played some beautiful passing," said Cahill after the match.
"I set one in there with Eric (Alexander) and pulled Johnny (Steele) in from the left and had Lloyd (Sam) breaking was a bit of a luxury today.
"It seemed really nice but the discipline and consistency has to be there and that's what we said before the game and I suppose a lot of people are looking at us to see if we could pull this off because Toronto is a good team and we did it. We made it difficult for ourselves.
"The only way they were going to score was us making a mistake. But in the end we kept knocking the door down and we got the win."