The Chicago Fire did not look like a team in the midst of a race for the Eastern Conference title on Wednesday.
Chicago had a chance to cut Sporting Kansas City's lead atop the East to just two points, but instead was held to a shocking 3-1 home defeat to the Philadelphia Union at Toyota Park to remain five points adrift of the lead.
The Fire (16-10-5) have lost two straight to remain tied with Red Bull New York on 53 points apiece, while the Union (9-15-6) have won two of their last three to improve to 33 points on the season.
The Union made the brighter start of the two sides and claimed a goal for their efforts in the seventh minute. Danny Cruz split the Fire defense with a through ball as Jack McInerney latched on and fired a low shot past Sean Johnson.
Daniel Paladini came within inches of getting Chicago on level terms in the 19th minute, but his free kick struck the woodwork to leave the home side down a goal.
The Fire were made to rue that miss in the 67th minute when Philadelphia doubled its advantage. Gabriel Gomez got on the end of a headed pass from McInerney and unleashed a rocket on the half-volley that made its way into the upper corner of Johnson's net.
Chicago was able to pull one back quickly as Dominic Oduro beat Zac MacMath with a shot to the near post two minutes later.
Guillermo Franco was sent off for a reckless challenge on Brian Carroll in the 79th minute, making Chicago's task of a comeback even tougher.
The Union used the extra man to put the winning result beyond any doubt as Michael Farfan centered a pass for Antoine Hoppenot to tuck home with a neat finish three minutes from time.