The Philadelphia Union wasted a huge chance to climb up the MLS table as they could not take advantage of Wyatt Omsberg's red card.
The defender was sent off following a foul on Cory Burke on the edge of the penalty area, which was viewed as a red card following a VAR consultation.
Chicago had taken the lead through Przemysław Frankowski as he headed past Andre Blake following a nice cross from Boris Sekulić.
Kai Wagner brought Philadelphia level from the free-kick that came from the red card as his low-drilled effort went underneath the wall and past Bobby Shuttleworth.
Both Andre Blake and Cory Burke returned to the starting XI following Jamaica's elimination from the Gold Cup. Jamiro Monteiro was absent, and Sergio Santos was suspended after an incident during the defeat against Orlando City.
Cory Burke came close to giving the Union an early lead. He did brilliantly to bring down a crossfield pass with his chest and managed to get a shot away, but he dragged it just wide of the far post.
In the 10th minute, Przemysław Frankowski headed Chicago into the lead. The visitors managed to get possession around the Union penalty area, and Boris Sekulić curled a cross into the box. Frankowski managed to get his head on the dangerous ball and found the back of the net, leaving Blake with no chance.
Burke had another opportunity for the Union in the 25th minute. Daniel Gazdag curled a ball into the box, and the Jamaican was first to meet the pass. He headed it towards the goal but was unable to find the target.
Burke managed to have another big chance. Alejandro Bedoya's long ball gave the Jamaican the opportunity to latch onto the ball ahead of Wyatt Omsberg and stab an effort towards goal as Bobby Shuttleworth came to close him down. Burke missed the target and ended up colliding with Shuttleworth, which left both players down hurt. However, that was just the beginning of the chaos.
The referee was then sent to VAR to check whether there had been a foul on the Union forward as he got towards the penalty area. The referee believed that Omsberg had made contact with Burke, leading to him losing his balance as he tried to squeeze the ball into the net. Omsberg was red-carded, and the Union had a free-kick.
From the resulting free-kick, Kai Wagner put Philadelphia back on level terms. He drilled his shot underneath the wall and into the back of the net as Shuttleworth could not get near the effort.
Gazdag had a great chance to put the Union ahead in first-half stoppage time. He did well to weave his way into the box and found himself in space inside the area. He tried to curl his shot into the far corner but instead managed to slice it well wide of the target.
Wagner came close moments later. He got the ball wide of the penalty area and aimed a cross into the box. The cross was overhit and clipped the top of the crossbar, giving Shuttleworth a moment of panic.
HALF-TIME: Philadelphia Union 1-1 Chicago Fire