With the Chicago Sky’s front-court duo of Sylvia Fowles and Elena Delle Donne on the floor, the Washington Mystics probably expected to see some of the best and most versatile post play the WNBA had to offer Tuesday night. To their surprise, they got that type of play from their own Kia Vaughn.

An on-and-off starter averaging 5.5 points entering the matchup, Vaughn slashed, finessed and battled her way to a season-high 21 points in her best performance of the season. But Delle Donne and Fowles spoiled Vaughn’s performance, combining for 40 points to help the Sky overcome a fast Mystics start in a 79-73 win at Verizon Center.

Vaughn, whose season high was 10 points coming into Tuesday, scored 13 in the first quarter.

“I just take what the team gives me,” Vaughn said. “I didn’t wake up saying, ‘This is going to be the game.’ I just try to come prepared every game.”

The 6-foot-4 Rutgers product dodged Delle Donne and sneaked behind Fowles time after time, repeatedly finishing even as that duo closed in on her. When they collapsed into the paint, Vaughn stepped back for open jumpers.

“I just kept moving without the ball. [Crystal Langhorne] found me cutting to the basket. My teammates got the ball to me when I would screen and pop,” she said.

Delle Donne, returning after missing two games with a foot injury, showed few effects from the layoff, making 7 of 17 shots (including three three-pointers) en route to 24 points.

“She gives them a three-point threat to stretch the floor,” Coach Mike Thibault said of Delle Donne. “It makes it harder to help and rotate when she’s at the three-point line.”

Her ability to hit from long range opened up shots for guard Courtney Vandersloot, who scored a season-high 19 points.

After trailing by four at halftime, Chicago led by seven just under five minutes into the third quarter, when Washington was just 1 of 16 from the field.

By the time Vaughn ended the drought with a jumper with 6:28 left in the game, Chicago had a four-point lead.

“Sometimes we catch teams a little bit complacent at the start of the game, and when they up their defensive pressure, we don’t necessarily execute like you need to,” Thibault said of the scoring drought. “You have to be a little bit mentally tougher. You have to work a little harder to get open. You have to be able to make one more pass without turning it over.”

But while the Mystics were within two with a minute to go, Vandersloot and Delle Donne each provided a dagger in the final 90 seconds to seal the win.

Despite the loss, the Mystics (12-15) are still in firm possession of one of the four Eastern Conference playoff spots, a half game back of the Indiana Fever for third and 61 / 2 games back of the conference-leading Sky (18-8).

DREAM 88, LYNX 75: Tiffany Hayes scored 23 points, and host Atlanta recovered after blowing a 17-point lead in the first half against Minnesota.

WNBA scoring leader Angel McCoughtry had 19 points and Erika De Souza added 16 points and 16 rebounds as Atlanta (14-9) scored the first 10 points of the fourth quarter and went on to its third straight win — all at home.

Rebekkah Brunson (Georgetown) had 16 points and 14 rebounds and Seimone Augustus added 14 points for the Lynx (18-7), who began the night a half game ahead of Los Angeles for the Western Conference lead.

MERCURY 89, SHOCK 86: Diana Taurasi had 28 points and 10 assists to help visiting Phoenix (14-12) beat Tulsa (8-18) for the third time in 11 days.