Sporting Kansas City have missed the chance to extend their lead atop the MLS Eastern Conference to four points by falling to a 1-0 defeat at Chicago Fire.
The only goal of the game came in the 13th minute, when Mike Magee's cross found Hunter Jumper and he beat Jimmy Nielsen with a diving header.
Peter Vermes's men had plenty of chances to find an equaliser, but they found Chicago goalkeeper Sean Johnson in top form between the sticks.
The win sees Frank Klopas's team move into sixth place, above New England Revolution.