Kia Vaughn, left, shown battling Connecticut’s Alyssa Thomas on Aug. 10, was suspended one game for a flagrant foul committed during that loss the Sun. (Jessica Hill/AP)

All Washington Mystics center Kia Vaughn could do Wednesday was watch helplessly as her teammates rallied from multiple double-digit deficits in the first half, then narrowly lose to the Chicago Sky when a win would have secured a playoff berth.

Vaughn was unavailable because of a WNBA-mandated suspension for elbowing Chiney Ogwumike during Sunday’s 89-81, double-overtime road loss to the Connecticut Sun. When the Mystics visit Mohegan Sun Arena again for Friday night’s rematch, Vaughn is set to be back in the lineup and eager to contribute.

Washington (15-17) needs one win in its final two games to qualify for the postseason for a second straight year. The Mystics will close the regular season Saturday night at home against the New York Liberty.

“Yeah, I was frustrated,” said Vaughn, who had started all 31 games until Wednesday. “I think it was a bit of almost every emotion that is negative when I was watching the game, and I couldn’t be there.”

Even without their leading rebounder and fifth-leading scorer, the Mystics kept it close against the Sky. Rookie Stefanie Dolson started in place of Vaughn and finished with 12 points and 10 rebounds. The No. 6 pick in April’s WNBA draft also was the primary defender against Sky all-star center Sylvia Fowles, who had game highs of 21 points and 16 rebounds.

In Sunday’s game against the Sun, Vaughn missed eight of her 10 shots and was on the floor when forward Kelsey Griffin collected an offensive rebound and scored on the putback to tie the game as time expired in regulation. Early the third quarter, Vaughn was called for a loose ball foul when she elbowed Ogwumike in the back of the head, forcing the rookie forward from the game.

The foul was upgraded to a flagrant 2 and the suspension issued upon review by the league office.

“We can’t be down,” Dolson said. “We can’t dwell. We just know that next game is a big game, too. We’ve got to win that, and we’re in the playoffs.”

The Mystics had beaten Connecticut three straight times before Sunday, when guard Alex Bentley scored 18 points and center Kelsey Bone added 15 points and 11 rebounds, all defensive.

The Sun also got 11 points from forward Alyssa Thomas, whose driving layup between two defenders with 1 minute 20 seconds left in double overtime provided an 81-77 lead.

The three-time ACC player of the year from Maryland is having the most productive month of her rookie year. Thomas has scored in double figures in four of five games in August, and her 11 points Sunday were her most against Washington this season.

“It’s just been a learning process,” said Thomas, who originally was drafted by the Liberty before being traded to the Sun. “Of course we haven’t won like we’ve wanted to but definitely have a lot of youth, and we’ve all been learning as a team.”

The Sun (12-20) is the only club eliminated from Eastern Conference playoff contention. Washington, meanwhile, has the same record as the Sky but loses the tiebreaker for second place. The teams split the four regular season games head-to-head, and the Sky will finish with the better conference record.

The Indiana Fever clinched a playoff berth Thursday night by defeating the Liberty. New York is now two games behind Washington in the Eastern Conference standings.

“It doesn’t have to be pretty, doesn’t have to be great. We just need a win,” Mystics forward Monique Currie said. “We’re going to go to Connecticut, and we’re going to dig down deep. We’re going to fight. We’re going to do whatever we can except throw elbows because we don’t want to have anybody suspended again, but we’re going to do whatever it takes to win the game.”