Omar Gonzalez scored the tying goal in the 80th minute to help Toronto FC rally to a 2-2 draw with the host Chicago Fire on Sunday in Bridgeview, Ill.
Pushing for a top-four finish in the Eastern Conference and first-round playoff home game, Toronto (47 points) extended its unbeaten stretch to 3-0-6 in its last nine matches.
Chicago (39 points), meanwhile, is undefeated in four straight, but was eliminated from playoff contention following New England's 2-0 win over New York City FC on Sunday.
The Fire, though, answered when a streaking Aleksandar Katai left-footed the ball in the net in the 68th minute.
Chicago took a 2-1 lead nine minutes later via Fabian Herbers' header off a tight cross from Nico Gaitan.
Gonzalez, though, sent home his own brilliant header off Alejandro Pozuelo's corner to level the match shortly after, and stun the Fire supporters.
Altidore nearly put Toronto on the board twice within a matter of one minute in the first half.
First, he was denied by Kronholm in the 13th minute. A minute later, it appeared Altidore sent home a Kronholm rebound, but the veteran forward was whistled for a foul in the box.
Chicago nearly answered in the 23rd minute when Nemanja Nikolic got behind the Toronto back-line at the far top of the box. However, Nikolic was unable to get much on the ball and TFC keeper Quentin Westberg made a rather easy kneeling save.
Four minutes later, Chicago's Przemyslaw Frankowski hit the woodwork on a cross from C.J. Sapong. Kronholm, meanwhile, came up big again with a save on Gonzalez's direct attempt off a corner on 33 minutes.
This was the Fire's final game at the suburban Chicago stadium that's been their home for 14 years. The club will move back to the lakefront at Soldier Field for the 2020 season.