The 38-point margin of victory set an Atlanta franchise record.
Sancho Lyttle had 15 points and 12 rebounds for Atlanta (5-3). De Souza had eight rebounds for the Dream, who held a 51-32 advantage.
Chicago’s Elena Delle Donne, who scored a career-high 33 points Friday in a 102-88 loss to Los Angeles, had a season-low seven and made only three of 10 shots. Allie Quigley led the Sky with 11 points. Jessica Breland had 10.
Delle Donne, the 2013 WNBA rookie of the year who began the night second in the league with a 24.4 points average, scored only two first-half points.
Atlanta, which led 56-31 at the break, set season marks for most points scored and fewest allowed in a half.
The Dream’s previous biggest win was by 33 points — 92-59 over Los Angeles on June 15, 2012.
Tiffany Hayes had 11 points, and rookie Shoni Schimmel scored 10 for Atlanta.
Atlanta set the high-scoring pace with a 30-16 lead in the first period, its highest total in any quarter this season. De Souza helped the Dream establish an inside advantage by scoring the game’s first two baskets on a follow shot and a drive to the hoop.
The Dream snapped a three-game losing streak to the Sky, including an 87-73 defeat at Chicago on May 24.
The Sky (5-3) fell out of sole possession of first place in the Eastern Conference. Chicago finished first in the East last season, but Atlanta advanced to the WNBA finals for the third time in four years.