Aerial Powers scored in bursts, Tianna Hawkins was ferocious on defense, and Emma Meesseman muscled her way to another strong shooting night, but none of it could offset the absence of Elena Delle Donne in Game 2 of the WNBA Finals on Tuesday night at Entertainment and Sports Arena.

The WNBA MVP exited the game for good a little more than three minutes into the first quarter with back spasms, and the Connecticut Sun took advantage in a 99-87 win that evened the best-of-five series at a game apiece. Game 3 is Sunday in Connecticut, with the unusually long layoff owing to the league wanting to get at least one game of the Finals on ABC.

After Tuesday night, the Mystics may be thankful to have more time to regroup.

“It’s a pretty simple game: When you give up 90 points to their starters, 56 points in the paint and 17 offensive boards for 28 points, that’s a tough way to win a game,” Mystics Coach-General Manager Mike Thibault said. “Give them credit. Jonquel [Jones] was great, bounced back from the other night. . . . But the rebounding was a huge concern. When Elena went out — I thought that she did a terrific job in Game 1 on Jonquel on the boards, and that went out the door. So we’ve got to do it the hard way.”

The Mystics appeared shaken from the moment Delle Donne left the court, even though they weren’t aware of what, exactly, her injury was. She headed back to the locker room, where a group of Mystics medical staffers reportedly worked on her back for the majority of the game. With just under 10 minutes to play, she was officially ruled out.

Delle Donne, 30, has had problems with her back before — it was a back issue that hindered her during her first WNBA ­Finals appearance in 2014 with the Chicago Sky. Last week, during the semifinals, she arrived at the team’s first practice in Las Vegas with her lower back wrapped. She and Thibault said the extra support was to help with stiffness after a long flight, and she played with the wrap on in Game 3 of that series.

Thibault said Delle Donne will get an MRI exam Wednesday.

The Mystics did not wilt in her absence, even drawing even early in the fourth quarter, but ultimately they couldn’t match the Sun’s firepower.

Meesseman scored 23 points on 10-for-17 shooting going up against 6-foot-6 Sun center Jones, a George Washington graduate. Hawkins scored 16 points to go with six rebounds, and Powers added 11 points, most of which came in a third-quarter run. Guard Kristi Toliver was the only starter in double figures with 13 points and seven assists.

Washington shot 47.2 percent overall and 31.8 percent from the three-point line. The Mystics seemed unable to settle down after their franchise centerpiece went down, and the Sun — already on solid footing thanks to a stronger start than their slow first quarter in Game 1 — seized upon Washington’s uncertainty.

“We’ve had situations before like this when great players have gone down in games, and there’s a real tendency to relax. There’s a tendency to say, ‘Oh, maybe things are going to be easier,’ ” Connecticut Coach-General Manager Curt Miller said. “ . . . But this franchise has played stretches without her before. So we knew that we weren’t going to get an easy break just because she was out.”

Focus intact, Connecticut played through Jones (32 points, 18 rebounds including nine offensive boards) with Courtney Williams (22 points) playing second fiddle on an offense that attacked the struggling Mystics. On defense, Connecticut out-rebounded Washington by a whopping 41-27 margin in what many Mystics players said was their cardinal sin of the night.

Alyssa Thomas was free to drive without Delle Donne’s presence and added 21 points to a team that played hard from whistle to whistle, rarely letting up despite Delle Donne’s injury.

“We could have pulled this out if we would have bought into the defensive end a little bit more,” Mystics starting guard Natasha Cloud said.

Once Washington settled down in the second half, it made a series of runs and finally pulled even at 76 with barely more than eight minutes to play. But the ball started sticking on the Mystics’ offensive end, and when it ended up in Toliver’s usually steady hands, she missed three consecutive shots against the Sun’s strong defense.

Connecticut didn’t waste the opportunity, pulling back ahead by six points in 71 seconds, and Washington never got another whiff of the lead.

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