From there it was all the home side with Folan grabbing a second and then Omar Cummings wrapping up proceedings in stoppage time to send them top of the Western Conference table and giving them the best record in the league.
Coach Smith said his namesake's 71st minute goal came at the perfect time as he felt a draw was on the cards if his side couldn't hit back quickly after Quaranta's equaliser.
"There was a shift in the game just before DC scored and I felt they had us on the rack at one point," Smith said. "To strike back so quickly, that was real kick in the teeth for them and, for me, the most important moment of the game."
And Folan, who was playing just his second match for the Rapids, said it was nice to contribute to his new club whose fans were full of support for him with a standing ovation when he was subbed late in the piece.
"I've played in front of bigger crowds, but the atmosphere today was better than some of those," Folan said after the game. "Credit to everyone that came. They made a lot of noise and drove us on as well.
"It's always nice to come out and hear that and I'm very thankful,' he said. "That brought a smile to my face."