Allie Quigley scored 19 points to lead five Chicago players scoring in double figures, Candace Parker added 14 points, eight rebounds and seven assists, and the Sky never trailed in their 91-75 win over the Phoenix Mercury on Saturday.
The game was a rematch of last season's WNBA Finals that Chicago won. The Sky have won both meetings between the teams this season.
Chicago (15-5) has won five games in a row and eight of its last nine to move into a tie with the Las Vegas Aces atop the league standings.
Kahleah Copper had 12 points, Rebekah Gardner scored 11 and Emma Meesseman 10 for Chicago.
Parker hit a 3-pointer and then found Courtney Vandersloot for a layup to give Chicago a 9-2 lead and the Sky closed the first quarter with a 23-5 run to make it 32-12 when Dana Evans hit a 3 at the buzzer.
Skylar Diggins-Smith led the Mercury with 25 points and four steals. Diamond DeShields added 21 points and nine rebounds in 22 minutes of action and Sophie Cunningham finished with 12 points. Diana Taurasi finished with a season-low two points on 1-of-6 shooting.
Phoenix (9-12) had its three-game win streak — which matched the Mercury's longest of the season — snapped and lost for the first time since the franchise and 2012 WNBA MVP Tina Charles, who signed a free-agent contract with the club in February, mutually agreed to part ways on June 25.
The Sky are 12-3 this season when scoring at least 80 points.