From left, Liberty guard Sabrina Ionescu, forward Breanna Stewart and...

From left, Liberty guard Sabrina Ionescu, forward Breanna Stewart and guard Courtney Vandersloot celebrate after scoring against the Mystics during the second half at Barclays Center on Tuesday. Credit: Noah K. Murray

A ticket to the WNBA semis was right there for the Liberty.

They could take advantage of their home-court advantage in the best-of-three opening round and finish off a two-game sweep of Washington Tuesday night at Barclays Center.

But if they lost, they would be forced into a win-or-else Game 3 showdown Friday night in D.C.

“We’d rather stay home and rest our bodies after tonight,” Betnijah Laney said after the Liberty’s morning shootaround.

They will get the rest, and they will need it. The second-seeded Liberty grabbed their ticket, but they had to work overtime for it.

They outlasted the seventh-seeded Mystics, 90-85, and advanced to the semis for the first time since 2015.

So the Liberty will play at 1 p.m. Sunday back at Barclays against Wednesday night’s Game 3 winner between Connecticut and Minnesota.

“It means a lot,” Breanna Stewart said. “I don’t think we’re thinking about getting this team back to somewhere the Liberty hasn’t been in eight years. But it’s the first time we’ve been able to do it as a group.”

Stewart led the group with 27 points, and she grabbed nine rebounds. Jonquel Jones stood out, too, with 19 points and 14 rebounds. Laney also scored 19.

Laney gave the Liberty an 80-79 edge in OT with a fallaway jumper in the lane. Stewart spotted Courtney Vandersloot underneath for a layup. And then Vandersloot hit a 20-footer from the left side, and it was 84-79 with 2:28 left.

The Mystics cut it to one, but Jones made a layup for an 86-83 edge with 49.6 seconds remaining. Ariel Atkins cut it to one with two free throws. Jones made a turnover, but Brittney Sykes then turned it over for Washington.

Stewart was fouled with 11.8 on the clock, and she hit two free throws for an 88-85 lead.

Washington called for time. Atkins missed a three. Stewart was fouled. She made two more. And that was it.

“We just didn’t have enough in our tank,” said Natasha Cloud, who topped the Mystics with 33 points.

It was 71-65 Washington with just under four minutes left in regulation. But the Liberty were unfazed, going on a 9-0 run.

Vandersloot fed Jones for a layup and a 72-71 lead with 1:38 left. Stewart blocked an Atkins shot and then Atkins was called for a travel. Stewart followed with an 11-foot jumper for a three-point advantage, 44.8 on the clock.

Sykes then nailed a three from the left corner to tie it with 33.5 left.

But Cloud made a steal of a Jones pass and was fouled by Jones, and then hit two free throws for a 76-74 lead.

After a Liberty timeout, Stewart missed a drive, got the rebound and Sabrina Ionescu ended up being fouled with 12.6 to go. She missed the first. One more to come.

“We knew we had to miss,” Liberty coach Sandy Brondello said.

The 6-6 Jones grabbed the huge rebound and was fouled with 11.3 showing.

What was Jones thinking?

“That I had to redeem myself after turning the ball over, honestly,” Jones said.

She hit two to tie it at 76-76.

“Those moments are certainly heartbreaking,” the Mystics’ Elena Delle Donne said.

After a Washington timeout, Cloud threw the inbounds pass away. Then Vandersloot turned it over — overtime.

“We didn’t stop playing until the final buzzer,” Stewart said.

The Liberty had constructed a 46-35 lead by halftime. After being held to 13 in the third, their lead was just 59-56.

But they survived and advanced.

“We’ve been battle-tested,” Stewart said. “We’ve gone through all the things in the regular season for these moments.”

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