Mohegan — Courtney Williams can deal with late-game pressure.

Needles, on the other hand, no way.

Connecticut was unraveling late in the third quarter of Sunday’s game against the Los Angeles Sparks, its 19-point lead quickly evaporating like a Popsicle on a Phoenix highway, while Williams was in the back getting a hole drilled into her toe to release the blood from a clot and took two shots to numb it.

“I was holding the doctor’s hand,” Williams said. “I don’t like needles. … I know it sounds crazy because I’ve got tattoos, but it’s different.”

One does what they must during playoff basketball, which Sunday’s game was for all intents and purposes.

And while the Sun didn’t ace the test, they still passed it.

Connecticut survived the Sparks for an 89-86 win on the final day of the WNBA regular season before 8,040 at Mohegan Sun Arena, and earned an all-important bye into the second round of the WNBA playoffs.

“Alright, that was a piece of cake,” Sun head coach Curt Miller deadpanned to start his postgame press conference.

Connecticut, for the second straight season, finished 21-13 and earned the fourth overall playoff seed.

The Sun will host a second-round game on Thursday at 8:30 p.m. (ESPN2) against the highest remaining seed — either the No. 5 Phoenix Mercury, No. 6 Los Angeles, or No. 7 Minnesota Lynx. The game is single elimination.

The Connecticut-Los Angeles matchup was the most important one in the league on Sunday because the winner would get the fourth seed and the loser would have to play in Tuesday’s one-and-done first round.

Connecticut, which was 12-12 on July 20, won nine of its final 10 games. It also won its final seven games at Mohegan Sun Arena to tie the first-place Seattle Storm and second-place Atlanta Dream for the best home record (13-4).

“I can’t be more proud of our players,” Miller said, “stepping up to the plate against a lot of really, really talented teams and taking care of business at home. ... So proud of our team.”

Jasmine Thomas led Connecticut with 27 points, five rebounds and five assists. She also made her final two free throws as well as a technical free throw with 1.2 seconds remaining to help pull the Sun through.

Thomas, over the past three Sunday afternoons at home, combined to shoot 50 percent with 22.7 points, 5.3 assists and two steals.

“I like the early games,” Thomas laughed. “I don’t know. It’s just a confidence thing. When I’m feeling good, when my body feels good, and I don’t get in my head, I just play free. It’s not just scoring, it’s everything I feel like I impact the game in good ways.”

“There was a determination by our leader," Miller said. "Jasmine Thomas was literally everything we could’ve asked for tonight. What we talked about was our will going to be bigger than (the Sparks’) will at halftime? There’s no one will bigger than Jasmine's, and she just brought us along.”

Jonquel Jones had 17 points, nine rebounds and seven assists for the Sun. Williams played her best late as she scored eight of her 13 points in the fourth quarter.

Shekinna Stricklen added 10 points and four rebounds, Morgan Tuck added 10 points and two steals, and Alyssa Thomas had seven rebounds, four assists and two steals.

Connecticut outshot the Sparks, 50.8 to 39.5 percent. It also made 11 of 20 3-pointers (55 percent).

Candace Parker had 20 points, 10 rebounds and two steals for the Sparks (18-15). They'll host defending champion Minnesota in Tuesday's first round in a rematch of the previous two WNBA Finals.

The Sun’s Chiney Ogwumike (knee) missed her second straight game. Los Angeles’ Nneka Ogwumike (illness) also sat out.

Connecticut led by as much as 62-43 with five minutes, 44 seconds left in the third quarter and Parker on the bench.

Essence Carson (14 points) and Odyssey Sims (11 points) came off the bench and helped Los Angeles shred Connecticut’s lead. Chelsea Gray ended the third with a 3-pointer as the Sun’s lead shrank to 69-63.

“You saw the heart of a champion in L.A. not going away tonight,” Miller said.

Parker’s contested, off-balance 3-pointer cut the Sun’s lead to 86-84 with 5.2 seconds left.

Jasmine Thomas made two free throws with four seconds remaining.

Jones fouled Riquna Williams as she missed a 3-pointer with 1.2 seconds left. Williams made the first and the third. The Sun called timeout so they could inbound on the other side of the floor.

Parker was called for a technical foul on the inbounds play as Los Angeles was trying to force a delay of game call, which teams cannot do in the final two minutes of regulation or overtime.

“That was on me,” Los Angeles head coach Brian Agler said. “It didn’t really matter because with one second left, we were going to have to hit a three.”

Thomas made the free throw, then got the inbounds pass and ran off the last second.

“While L.A. made some big plays down the stretch and made us work for it, we got to the finish line,” Miller said. “It is a huge opportunity to now have Monday off.”

n.griffen@theday.com

WNBA PLAYOFFS

First Round

Tuesday's Games

Dallas at Phoenix, 8:30 p.m.

Minnesota at Los Angeles, 10:30 p.m.

Second Round

Thursday's Games

Lowest remaining seed at Washington, 6:30 p.m.

Phoenix, Minnesota or Los Angeles at Connecticut, 8:30 p.m.

Note: All first and second-round games are single eliminaton and will be televised on ESPN2