LOUISVILLE — No. 4 Louisville blew almost all of a 17-point, second-half lead, but hung on as Russ Smith scored 17 of his team-high 21 points after halftime to turn back in-state rival Kentucky 80-77 on Saturday before a record crowd of 22,810 at the KFC Yum! Center.

“Defensively, and offensively for that matter in the first half, we played awesome,” said Louisville coach Rick Pitino. “But it’s a tribute to a young team to be able to comeback. They’re an excellent basketball team and they are just going to keep getting better and better. And [Wildcats’ coach] John [Calapari] is the right guy to get them there.

“It was a great win for us because we had to battle a lot of foul trouble. We survived with some good plays by Chane [Behanan] and Russ, but we lost our defensive presence in the second half because of foul trouble. Overall, I’m delighted other than a couple of bad plays we made down the stretch in our zone.

“But — and in saying I think Kentucky will get better — I don’t think that we’ve reached our potential.”

It was just the third win in the last 10 tries for the Cardinals over the Wildcats as Kentucky had won four in a row, including a Final Four victory last season. Neither team has ever won five in a row in the series.

“This probably ranks as one of the top five biggest wins of my life,” said Smith.

Smith has had success in the past, including last season’s loss at Rupp Arena in which he scored what was then a career-high 30 points.

Louisville (12-1) led 36-28 at halftime, then opened the second half with a 15-6 run to take a 51-34 lead. Kyle Wiltjer then hit back-to-back 3-pointers to start Kentucky (8-4) on a 10-0 run. Foul trouble hindered the Cardinals’ normal aggressive defensive style as they built the lead back to 61-51 before Kentucky closed to within 63-61 on a basket by Ryan Harrow with 5:32 left in regulation.

“The foul trouble took away some of our aggressiveness. But we just tried to stay positive through it all and hope for the best,” Smith said.

Louisville kept fighting and seemed to have things in control as Behanan’s dunk off a Gorgui Dieng assist gave the Cardinals a 77-70 advantage with 44 seconds left.

But then the Cardinals’ Peyton Siva then committed what has become the ultimate sin on a basketball court — foul a shooter on a 3-point attempt.

Siva fouled the Wildcats’ Archie Goodwin, who hit the shot and the ensuing free throw. Suddenly what seemed to be a victory at hand was a one-possession game with Louisville leading 77-74 with 33.7 seconds left. The play also sent Siva to the bench with his fifth foul.

Kentucky then immediately fouled Smith on the inbounds play. Smith hit 1-of-2 free throws, but Kentucky then threw the ball away leading to a wide-open Behanan dunk. Goodwin hit another 3 just before the buzzer for the final margin.

Behanan finished with 20 points, while Siva totaled 19. Dieng, seeing his first action since breaking a wrist during the Missouri game in the “Battle for Atlantis,” scored six points and tied three other Cardinals for the team lead in rebounds with seven.

Goodwin scored a game-high 22 points to lead the Wildcats. Harrow added 17 points, while Wiltjer finished with 14.

“Hat’s off to them — what a good team they are,” said Calapari. “They play hard, they play aggressive, they play rough and their guard play is outstanding.

“And this is not to take anything away from their effort, but I told my team all week — you get us close and I’ll help us get over the edge. Let’s make this close and they did. And then down four and with the ball, I didn’t call that timeout. I’m standing there thinking timeout and I didn’t call it. That there effectively ended the game.”

Kentucky won the boards 39-36, but Louisville is 4-0 this season in games in which they’ve lost the glass.

And the Wildcats 7-foot freshman, Willie Cauley-Stein brought a new, yet to be named stat to the table has he not once, but twice missed three free throws after being awarded an extra shot due to a lane violation.

Free throws were a big flaw in the Wildcats’ armor as they made only 11-of-23.

Louisville, which has had trouble at times from the line this season, hit 17-of-25, hit 48 percent from the field and only turned the ball over nine times. This day it was good enough for a victory.

Louisville will return to action on Wednesday as it opens Big East Conference action as it hosts Providence. Kentucky will return to action the same night, hosting Eastern Michigan.