The Fire raced into a two-goal lead with goals from Mike Magee and Juan Luis Anangono, but a stirring second-half revival from the visitors, with two goals from Joao Plata and one from Alvaro Saborio, gave Salt Lake all three points in the most dramatic of finales.
Anangono started up front in place of suspended top scorer Quincy Amarikwa, while Benji Joya replaced the injured Alex in the center of midfield. The visitors were unchanged from their 2-2 tie with Vancouver Whitecaps last time out, a game where they lost a win with two late goals from the 'Caps.
An eventful first half saw the Fire deservedly take the lead in the 22nd minute after enjoying the better of the opening exchanges.
And it was reigning MLS MVP Magee who was in the right place at the right time as he reacted instinctively to sidefoot home after Harry Shipp’s well-struck shot from 20 yards was parried by Nick Rimando.
RSL almost responded immediately when Saborio was denied by Sean Johnson from close range, while at the other end, a superb turn and pass saw Magee play Anangono in on goal, but he pulled his first-time volley wide from inside the box.
The Fire did double their advantage in the 31st minute when Greg Cochrane found space high on the left to receive Joya’s pass and his pinpoint center picked out the unmarked Anangono and the Ecuadorian headed powerfully home from six yards.
The outstanding Johnson then denied Saborio and Plata with two stunning saves to keep Salt Lake out, while Magee headed wide from a Shipp corner as the Fire went into the break 2-0 up.
Real were the first to threaten in the second-half as Saborio shot over twice in the space of six minutes before the hour.
Magee almost put the Fire 3-0 up in the 63rd minute when he got the better of Nat Borchers before hammering a shot off the crossbar, following which the Fire striker was booked for a handball on the rebound.
The lively Plata pulled one back for Salt Lake in the 72nd minute when he latched onto an incisive through-ball from Javier Morales to slot the ball low to Johnson’s right from 16 yards.
With a first victory of the season beckoning for the Fire, Salt Lake struck on the stroke of 90 minutes when Olmes Garcia’s cross from the left was missed by Bakary Soumare and Saborio slotted home from a yard out.
Saborio then turned provider three minutes into stoppage time when his left-wing cross found Plata at the back post, and the striker swept the ball home right-footed to give Real all three points.
Next up for the Fire is a road game at the New York Red Bulls on Saturday, while RSL visit the Houston Dynamo a day later.