Morrow put Dallas in front in the 10th minute. Chicago defender Rick Titus fouled Ronald Cerritos at the edge of the penalty area and Martinez swung the free kick in front of the net, where Morrow slipped through a pair of defenders and got his head on the ball.
Ronald Cerritos, struggling through a goal-scoring drought, put a shot off the far goalpost in the 47th minute.
Jason Kreis netted his sixth goal of the year in the 54th minute, finishing off a cross by Joselito Vaca while sliding through the penalty area.
Morrow got his second goal in the 60th minute, finishing off another pass from Martinez with a sharp header in front of the net.
Colorado got one back in the 65th minute after a bizarre incident in the penalty area. As the Rapids pushed forward, a whistle from the stands caused the Burn defense to pause. Colorado continued to press and was awarded a penalty kick following a hand ball in the box. John Spencer blasted the ball past Jordan to go 3-for-3 from the spot.
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