Terrence Williams scored 17 points and freshman Derrick Caracter came off the bench to score 16 first half-points and the Cardinals (21-8, 11-4 Big East) beat Connecticut 76-69.
"I think we're in," coach Rick Pitino said. "There has never been an 11-4 team not get in to the NCAA coming out of the Big East."
Louisville blew an early 11-point lead, and UConn (17-11, 6-8 Big East) tied the game at 58 on a 3-pointer from Jerome Dyson with 4:02 to go. They tied it again at 60 when Jeff Adrien hit a jumper for the Huskies at 3:31.
But the Cardinals scored on every possession after that.
"When the crowd gets loud, that's when you have to dig in and play hard," Williams said. "If we get good ball movement, no matter how loud the crowd gets, we're going to make shots."
Earl Clark's 3-pointer gave Louisville the lead for good, 63-60 with 2:53 to go. Edgar Sosa also hit from behind the arc with 1:15 to give Louisville a 68-63 lead, and the Huskies were forced to foul the rest of the way.
Louisville hit six consecutive free throws to secure the win, the final two coming from Williams.
"When (Sosa) hit last three, it took a little bit out of us," Dyson said. "We couldn't find the stops we needed."
Dyson hit 6-of-8 from 3-point range and scored 23 points to lead Connecticut. Jeff Adrien had 16 points for UConn, which had won four of its last five in league play, after starting the conference schedule 2-6.
The Cardinals looked to be in trouble early when David Padgett, who had 19 points in Louisville's 68-54 win over Connecticut on Jan. 22, picked up two fouls in the first 4:23. But Caracter replaced him and the 6-9 freshman scored all 16 of his points before intermission, outmuscling the Huskies underneath.
Pitino had suspended Caracter twice this season for issues on and off the court, but praised him Sunday for sticking with the program.
"We have made up our minds that he's either going to be a player, or he's got to pack it in and go home," Pitino said. "Never once did he say, 'I'm going to leave,'.... He just kept saying, 'I'm wrong, this is the place for me. I'm sticking it out.' He's never once wavered on that. That's why he's here today."
The Cardinals had 46 points in the paint, to 22 for UConn, and outrebounded UConn 36-29.
"The bottom line is that we didn't execute coming down, and they executed greatly," said UConn coach Jim Calhoun. "All we had to do really, the last four minutes to have a chance of winning this game ... was play defense, even 50 percent of the time."
Louisville hit just five of its first 14 shots and was outrebounded 9-2 early, but still led 11-9 with 11:24 remaining in the first half.
The Cardinals went on an 11-4 run to close out the half and led 38-29 at the break. Louisville has not lost this year when leading at the half.
UConn opened the second half on an 8-4 run. But Pitino called a quick time-out and the Cardinals scored the next six, stretching the lead back to nine.
The loss was a huge blow to Connecticut's NCAA chances. The Huskies do not have a win against a Top-25 team, have a losing record in conference, and an RPI of 87.