The victory was secured in a frenetic first 10 minutes of the second half as Quioto's two strikes, the second of which came from the penalty spot following an Anton Walkes foul on Joaquin Torres, immediately answered an opening goal from Atlanta halftime substitute Jake Mulraney.
The victory, at least for the time being, lifts Montréal back above the playoff line and knocks Atlanta down to eighth and out of the postseason berths in an ever-tightening race for the top seven.
Atlanta were on top for much of the opening half, but unable to make it count on the scoresheet. The returning Josef Martinez, who was later substituted off at halftime, had perhaps the best of the opportunities for the visitors when he was gifted the ball straight from the feet of Montréal goalkeeper James Pantemis but unusually failed to get his shot away before being crowded out by a defender.
There were also signs of Ezequiel Barco's red-hot form, first when he stung the palms of Pantemis with a shot from the edge of the box and then when he came oh so close to an AT&T Goal of the Year candidate after a sensational run that saw him cut inside and out Montréal defenders before a scooped shot was denied by the crossbar.
Montréal's best chance, meanwhile, came when Quioto glanced a header wide after a fine cross from Djordje Mihailovic.
But a lack of goals in the first half was spectacularly made up for in the opening minutes of the second. Atlanta got rewarded for their endeavors just three minutes into the second half when Mulraney cooly slid a shot past Pantemis on his right foot after a through ball from the other half-time arrival off the bench Luiz Araujo.
Yet Atlanta's work to finally get the lead was almost immediately undone. Just two minutes later, Quioto was played through down the right of the box by Torres. While it looked like Walkes had successfully pushed him wide, the Montréal attacker fired an unstoppable shot from the tight angle into the roof of Brad Guzan's net.
From an almost repeat scenario, Montréal were soon in the lead. This time Walkes elected to slide in on Torres in the box and while it was an honest attempt for the ball, he took the man and the referee pointed to the spot. Quioto did the rest, slotting into the bottom corner of the net, beyond the dive of Guzan, for his eighth goal of the season.
Despite their earlier attacking threat, Atlanta had little answer to falling behind, even after the return from injury of Franco Ibarra.
- THE BIG PICTURE: This could turn out to be a huge result in the wildly close race for playoff places in the Eastern Conference. All looked set for a big road win for Atlanta when they took the lead, but within seven minutes the game had turned on its head. After a fine run of form that propelled them into the playoff places, Atlanta have now lost two of their last three games and will be desperate for a win when they return to action in two weeks' time. Montréal, meanwhile, refuse to go away in the battle for the playoffs and crucially arrested a two-game losing streak to put them back above the line, at least for the moment.
- MOMENT OF THE MATCH: Quioto's opening goal, just two minutes after Atlanta had gone ahead, completely changed the complexion of a game the visitors might have expected to control after getting a deserved lead.
- MAN OF THE MATCH: Joaquin Torres deserves a strong mention, but Quioto gets the nod for doing the business in front of goal to deliver Montréal a crucial win.