The Fire put themselves in an impressive position, but it all fell apart as Real Salt Lake struck twice late to take the three points.
Chicago scored twice in the middle of the first half to take the lead. Mike Magee opened the proceedings in the 22nd minute with a poacher's finish. Nick Rimando saved a shot from outside the area, but left it to fall in front of his goal rather than ushering it wide, and Magee pounced.
Juan Luis Anangono doubled the Fire's lead eight minutes later. Charging forward into the box, he leapt and connected an unmarked header onto Greg Cochrane's lofted cross.
Joao Plata struck back for RSL in the 72nd minute. Collecting a pass from Javier Morales, Plata turned and stung a hard shot past Sean Johnson from the edge of the penalty area.
Plata's goal opened the door for a dramatic comeback. Alvaro Saborio found the net in the 90th minute when, unmarked in front of goal, a Abdoulie Mansally cross fell perfectly in front of him and he lashed it just over the line.
Plata's second completed an impressive comeback win in stoppage time. Saborio turned provider on this one, launching a long ball across to the oncoming Plata, who finished with a fantastic first touch.
Chicago is still looking for its first win of the MLS season, while Salt Lake is yet to experience defeat this campaign.