The free kick was set up when Mohammed Adams was called for a hand ball in the penalty area. Rusnak has six goals this season.
Chicago struck early when Aleksandar Katai scored in the fifth minute on a free kick. Katai came up empty at the 82nd when he fired a solid shot from the right that was just wide.
Chicago (4-6-7) extended its home unbeaten streak to seven. Real Salt Lake (6-8-2) has been outscored 8-1 in its last three games.