Angel McCoughtry scored 21 points on 8-of-17 shooting as the Atlanta Dream beat the Sky, 75-66, eliminating Chicago from postseason contention.
With the Sky's loss, the New York Liberty earned the final postseason spot in the Eastern Conference.
Sancho Lyttle also contributed 17 points and eight rebounds for the Dream, who have won seven of their last eight.
Carolyn Swords led four double-digit scorers with 16 points, but it wasn't enough for the Sky, who have lost four of six.
The Dream will wrap up their regular season at Connecticut on Sunday before beginning postseason play against second-seeded Indiana.
The Sky will host the Washington Mystics in their regular season finale on Saturday.