BRADENTON, Fla. -- Gabby Williams and Cheyenne Parker each scored 16 points, Courtney Vandersloot had a late steal, and the Chicago Sky beat the Washington Mystics 88-86 on Saturday night.

Allie Quigley added 15 points, Kahleah Copper scored 14 and Diamond DeShields -- who has seen limited action as she recovers from a knee injury -- had a season-high 10 points for Chicago (3-1).

Washington's Aerial Powers made 1-of-2 free throws to make it 84-all with 43.2 seconds left before Parker made a layup and Ariel Atkins hit two foul shots. Parker was fouled as she made a short jumper but missed the and-1 and the Sky led 88-86 with 5.9 to play. After the Mystics called a timeout, Vandersloot stole a pass from Emma Meesseman to seal it.

Atkins scored 24 points and Powers added 20 for the Mystics (3-1). Myisha Hines-Allen had 13 points, 12 rebounds and three steals.

Washington came into the game the lone undefeated team in the WNBA.

The Sky opened the fourth quarter with an 11-2 run to take a nine-point lead when Parker made a jumper with 6:43 remaining. Washington answered with a 12-4 spurt to trim its deficit to 79-76 nearly four minutes later. Williams hit a 3-pointer but after Hines-Allen made two free throws Atkins made a 3 and then two foul shots for Washington to make it 83-82 with 1:14 left.