The Timbers appeared to be continuing their good form, until Chicago found two goals in the second half to claw back a point.
Portland took the lead in the 33rd minute. Milos Kocic's long kick was headed down by Frederic Piquionne to Diego Valeri, who juked between Fire defenders Bakary Soumare and Jalil Anibaba to put his shot off the post and into the net.
Piquionne was involved again in his team's second goal just before the hour, as he dribbled to the endline, cut back and picked out Ben Zemanski's run. The midfielder hit a tidy, long-range finish with the side of his cleat.
Despite going down to a Timbers team that had lost just one game all season, the Fire found a way back into the match. Mike Magee scored in his second straight game since joining the Fire, taking advantage of a defensive mixup to tap home from close range.
Daniel Paladini leveled the 82nd minute, curling a free kick around the wall and inside the post to snatch a draw from what had looked like a home loss. Magee won the free kick.