Husidic scored in the 14th minute and Pappa extended the lead to 2-0 in the 74th as Chicago (3-3-4) won at home for the first time since April 24th.
Danny Mwanga pulled Philadelphia (2-6-1) within a goal in second-half stoppage time, poking a right-foot shot past Fire goalkeeper Andrew Dykstra.
Sebastien Le Toux had a chance to score for the Union in the 38th minute when he missed the top left corner with a long shot.
First half-1, Chicago, Husidic 3 (Nyarko, Mapp), 14th minute.
Second half-2, Chicago, Pappa 3, 74th. 3, Philadelphia, Mwanga 3 (Le Toux), 90th+.
Goalies-Philadelphia, Chris Seitz; Chicago, Andrew Dykstra.
Yellow Cards-Miglioranzi, Philadelphia, 22nd; Brown, Chicago, 45th; McBride, Chicago, 70th.
Referee-Abbey Okulaja. Assistant Referees-George Gansner. James Conlee. 4th Official-HIlario Grajeda.
A-14,658 (20,000)
Lineups Philadelphia-Chris Seitz, Danny Califf, Michael Orozco, Cristian Arrieta (Roger Torres, 45th), Jordan Harvey, Kyle Nakazawa (Danny Mwanga, 45th), Fred (Nick Zimmerman, 82nd), Stefani Miglioranzi, Shea Salinas, Sebastien Le Toux, Alejandro Moreno.Chicago-Andrew Dykstra, C.J. Brown, Wilman Conde, Krzysztof Krol, Dasan Robinson, Logan Pause, Baggio Husidic, Marco Pappa, Justin Mapp (Peter Lowry, 90th+), Brian McBride, Patrick Nyarko.
