A solitary goal from Dominic Oduro has earned Chicago Fire their first win of the season and inflicted a third consecutive MLS defeat on Philadelphia Union.
The Ghanian international struck in the 28th minute of the game at Toyota Park with a bullet header from a floated Marco Pappa cross.
Chicago were well worth the lead, having controlled the encounter for large periods and forcing Union goalkeeper Zac MacMath into three fine saves.
After doing well to hold Dan Gargan's firm header early on, the 20-year-old stopper made an excellent fingertip save to deny Sebastian Grazzini's 12-yard volley.
He then performed further heroics with a spectacular double-save to stop Oduro claiming his second of the night midway through the second half.
Philadelphia almost made the hosts pay for not taking their chances six minutes from time, but Paolo Tornaghi, who had been a mere spectator for most of the game, just managed to tip Gabriel Gomez's long-range effort over the crossbar.
