As Alexis Hyder marched to the free-throw line, her LSU team down a point to Tennessee with 3.4 seconds left, teammate Jenna Deemer got in her ear.

“Redeem yourself!” Deemer shouted over the frenzied crowd in the Pete Maravich Assembly Center. “Redeem yourself!”

Hyder didn’t have to be told. With 1:06 left, she froze Mercedes Russell with a dazzling flanking move to the basket but missed a layup that would have given the Lady Tigers a one-point lead. With 10.4 seconds left she lost her dribble near the top of the key, the last of seven turnovers on her feast or famine Sunday, and committed a foul with her team down two.

Now she had a chance to make everything right.

Hyder sank both free throws. And Tennessee’s Andraya Carter, who sent Hyder to the line with a shocking foul, came up well short on a desperation 30-footer at the buzzer as LSU stunned the No. 24 Lady Volunteers 57-56.

“I owed my team that,” Hyder said. “Literally. I really thought I lost it for them. I’d have been sick if we’d lost this game.”

LSU looked like a team sick and tired of losing. Ravaged by injuries and the June dismissal of All-Southeastern Conference senior guard Danielle Ballard, the Lady Tigers were just 8-18 overall and 2-11 in Southeastern Conference play coming in.

But they never quit. Finally, in the midst of LSU’s gloomiest season in two decades, they recorded a big, shining upset.

“Our kids just played with a lot of heart and fight,” fifth-year LSU coach Nikki Fargas said. “We didn’t give up. I’m so proud of our team for hanging in there. Even when it didn’t look like it was going our way, we found a way.”

It was the first home win in three tries for Fargas against Tennessee, where she played guard and was an assistant for legendary coach Pat Summitt.

Summitt made Tennessee women’s basketball a superpower, but this may have been a historic loss in a season of retreat for the Lady Vols.

Now 16-11 and just 7-7 in SEC play, they’re likely to fall out of The Associated Press rankings for the first time since 1985, a string of 565 consecutive polls.

“Hats off to LSU,” said fourth-year Tennessee coach Holly Warlick, her voice quaking with emotion. Warlick recruited Fargas to Tennessee, and the two have remained close friends.

“(The Lady Tigers) don’t look at their record. They just play basketball as hard as they can play. The whole team just really played hard.”

LSU trailed 10-6 in the first quarter but rode a 22-4 surge to a surprising 14-point lead, 28-14, with 2:34 left in the second on a fast break basket by Shanice Norton. The Lady Tigers led 28-18 at halftime, one of if not the lowest first-half point totals ever by Tennessee against LSU.

But the Lady Vols roared to life in the third quarter, retaking the lead 32-30 on a jumper by Diamond DeShields, who had a game-high 19 points. LSU answered with consecutive 3-pointers by Deemer — playing her second game after missing nine straight with an illness — to take a 39-37 lead to the fourth.

“There is always one quarter that we are really not good and we struggle to score,” Fargas said of LSU’s 11-point third. “When you have your best 3-point shooter back (Deemer) and Ann Jones (who missed seven games before Thursday’s loss at Texas A&M with an ankle injury), I think that played well to our psyche.”

Still LSU trailed 56-53 after Carter made a free throw following Hyder’s turnover and foul with 10.4 seconds left.

Rina Hill flew downcourt for a layup with 4.5 seconds left to make it 56-55. Norton fouled Russell at almost the same instant, perhaps a break for LSU, which had little time left.

The biggest break was to come as Russell missed both free throws. Hyder rebounded the second miss in the lane but was knocked down by Carter as she tried to head up court. LSU had Deemer positioned deep, but without the foul, the Lady Tigers might have been hard-pressed to get off a good shot.

“I’m glad they fouled me,” said Hyder, smiling. She finished with a team-high 17 points. Fellow forward Akilah Bethel had nine points and a game-high 12 rebounds before fouling out.

“It definitely fills our tank going into the SEC tournament,” Bethel said. “We have two games left. We put down a ranked team, and now we have our confidence. It can waiver sometimes, you know, losing and losing, but this definitely built our confidence in preparing us for what we’re about to face.”

The Lady Tigers host Florida at 7:30 p.m. Thursday in their home finale before wrapping up the regular season Sunday at No. 2 South Carolina. Then it’s off to the SEC tournament in Jacksonville, Florida.

“We’ve got a lot more basketball in us,” said Fargas, who became LSU’s second-winningest coach with her 92nd win, “and a lot more ‘Ws’ to go after.”

Follow Scott Rabalais on Twitter, @RabalaisAdv.