Mohegan — The Connecticut Sun had every element for a dramatic victory Sunday against the New York Liberty, not the least of which was the singular toughness which defined them all season long.

Sun All-Star Alyssa Thomas, injured at the start of the fourth quarter after being tangled up with New York’s Jonquel Jones, returned from the locker room and checked back into the game with 6 minutes, 52 seconds remaining, pulling Connecticut along with her in a quest to extend the best-of-five semifinal series.

Instead, it was New York which advanced to the WNBA Finals for the first time since 2002, scraping by with an 87-84 victory to end Connecticut’s season.

“This group, I told them in there it’s been a privilege to coach them,” Sun first-year head coach Stephanie White said, “that I’m so thankful that I get to ride with them. They’re resilient, they’re tough, tough-minded.

“You look on paper and you might not think that we’re gonna compete the way that we do but there’s no substitute for grit and toughness and willingness to sacrifice for something bigger than yourself. That’s part of what drew me here.”

Second-seeded New York will face the No. 1 Las Vegas Aces beginning Sunday on the West Coast.

For the Sun, the toughest of them all was Thomas, who finished with her unprecedented 11th career triple-double, third all-time in the postseason. She had 17 points, 15 rebounds and 11 assists.

Tiffany Hayes added 15 points and DiJonai Carrington 14, while Ty Harris made the late-game drama before the 8,196 raucous fans at Mohegan Sun Arena even more palpable with two late-game 3-pointers which pulled the Sun within one with 7.6 seconds to play.

Breanna Stewart, the league MVP and former UConn great, had 27 points and nine rebounds for the Liberty and Jones had 25 points and 15 rebounds. Jones is in her first season in New York after being traded from the Sun.

Stewart iced the game from the free throw line with 6.1 seconds remaining after Harris’s final 3-pointer drew the Sun within 85-84. The Sun came up empty on their final harried possession.

Connecticut was playing in its fifth straight semifinals, bidding to reach the Finals for the second straight year. Trailing 2-1 in the series, the Sun needed a win Sunday to send the semis back to New York for a deciding Game 5.

“Relief,” said New York coach Sandy Brondello of her sentiment as the final buzzer sounded. “We made some mistakes down the end but that’s what this game is about, just staying connected. It was a relief but joy. We’re all invested in it together.”

“To be honest, I don’t think I’ve fully processed what it means to bring this team to a WNBA Finals,” said Stewart, who is playing for the Liberty for the first time, as is Jones. “The fact that the Liberty hasn’t been to a Finals since 2002 is wild. To be able to have that and know that we have the entire city behind us is really, really special.”

In an electric atmosphere, the Liberty took a one-point edge into halftime, 45-44, after scoring the final six points of the second quarter, the last two on a fast break layup by Sabrina Ionescu with .7 remaining.

The Sun built a double-digit lead at 33-23 on back-to-back 3-pointers by DeWanna Bonner and Hayes, prompting a Liberty timeout with 6:08 to go in the second. At that time Stewart was 2-for-6 shooting for five points.

Following the timeout, Stewart scored seven straight points on a jump shot, a 3-pointer and a tip-in as the Liberty pulled within 33-30.

Connecticut led 44-39 after an offensive rebound by Olivia Nelson-Ododa and one free throw by Thomas, but New York ended the half with an offensive rebound by Betnijah Laney and four points from Ionescu.

The Liberty pulled ahead by as many as 11 in the third quarter as Jones caught fire, with the 6-foot-6 center scoring from inside, as well as effortlessly dropping a pair of 3-pointers, going 9-for-12 from the free throw line and engineering a key steal.

New York led 66-58 at the end of three quarters. It was 37 seconds later that Thomas was assisted from the arena after laying on the floor face down for several agonizing moments.

Asked to describe the injury and her later reappearance, Thomas responded: “No, we’re good.”

Without Thomas, the Sun took off on a six-point run on shots by Carrington, Hayes and Harris that brought them back within 66-64.

With Thomas re-entering, Connecticut took the lead with 3:54 to play on a 3-pointer by Bonner assisted by Thomas. Jones responded with a 3 but Thomas tied the score at 74-74. The Sun took their final lead on a free throw by Carrington before Stewart put the Liberty ahead for good with a 3 at 77-75.

The Sun won the first game of the series in New York 78-63, their first win over the Liberty this season. The Liberty responded with victories in Game 2 (84-77) and Game 3 (92-81).

“Certainly a congratulations to New York. They earned it,” White said. “We gave them a battle but we came up short.

“They’ve continuously stepped up to the challenge and they bust their butts every day. They compete at a high level and will themselves and our team to do things that I’ve never seen.”

v.fulkerson@theday.com