Both teams held each other scoreless for the first three minutes of the second half before the Mystics dropped in a pair of 3-pointers and went on an 8-2 run. The Sun climbed back to within 78-74 with six minutes left. The Mystics countered by feeding Delle Donne, who scored consecutive baskets, the second an absurd series of twist and turns around, over and through Alyssa Thomas, the Sun never getting as close again.

“Alyssa Thomas is an elite defender, and when she bodies up on 99 percent of the people in the league and they’ve picked up their dribble, she usually gets them stopped,” Suns Coach Curt Miller said. “But we all know that E.D.D.’s step-through in that last movement to the basket where she leans in and can create space and get her shot off — she’s the only person in the world that does that.”

The Sun see a need to get forward-center Jonquel Jones more involved in the offense. Jones, who ranks fourth in W.N.B.A. history in true shooting percentage through her first four seasons, is one of the most effective players on the floor, and, at 6-foot-6, causing defensive matchup problems no one can solve. That is, provided she gets the chance — she took only eight shots on Sunday, with Connecticut running its offense through other players instead.

“We talked about going back to that, trying to establish her early in the second half, at least getting her touches,” Miller said of Jones. “But we need those shots up.”

It will be a team effort to do so. Williams said she plans “to hype her up, remind her she’s the best player on the floor.”

Despite the loss, Williams, who finished with a game-high 26 points, didn’t sound worried.

“To be honest, I felt like I could do whatever I wanted to do,” Williams said. “I felt like I was getting to all the spots I wanted to get to. I felt pretty comfortable. We’ve just got to win the next game.”