SAN FRANCISCO -- Darrion Williams could barely make a shot for the first 30 minutes. He didn't miss when it mattered most, sending Texas Tech to an improbable spot in the Elite Eight.

Williams scored the go-ahead basket with 7.3 seconds left in overtime after tying the game with a 3-pointer in the closing seconds of regulation to lead Texas Tech to an 85-83 win over Arkansas on Thursday night.

"The heart of the team is Darrion Williams, and he's just a resilient guy," coach Grant McCasland said. "I mean I can't even explain it. I put faith in him because I do believe that he'll find a way in one-game scenarios to do whatever it takes to win. I honestly do. Whatever it takes."

The first overtime game of March Madness came thanks to a furious comeback by the third-seeded Red Raiders (28-8) from 13 points down with less than five minutes left against coach John Calipari's 10th-seeded Razorbacks (22-14).

Texas Tech advances to play top-seeded Florida in the West Region final on Saturday with a chance at the school's second Final Four trip after losing the title game to Virginia in 2019.

That idea seemed far-fetched for most of this game as Arkansas broke out to a double-digit lead early and was in control most of the way, leading by as many as 16 points in the second half, making the Red Raiders' comeback the third-largest ever in the Sweet 16. According to ESPN Research, Arkansas had the lead for 38 minutes, 53 seconds, whereas Texas Tech led for 3 minutes, 20 seconds.

"In the huddle, Coach kept saying, 'We're going to find a way to win this,'" guard Christian Anderson said. "No matter how much we're down, I think it was like 16 [points] with 10 minutes left or something. As a team we kind of had that look, like, 'We're not losing this game no matter what.' No matter if it's defensive, offensive rebounds -- we got to get defensive rebounds, steals. I know we had to find a way to make it happen, and at the end we did."

Williams helped will the Red Raiders down the stretch after opening the game by missing 13 of his 15 shots in front of a large contingent of his friends and family that came from Sacramento, California, for the game.

But the Red Raiders closed regulation with a 16-3 run behind three 3-pointers from Anderson and three baskets from Williams. The biggest came when Williams rattled in a 3 with 9.7 seconds left after Jonas Aidoo had missed the front end of a one-and-one.

Williams had missed eight of his first nine attempts from 3 before that make.

"Obviously they weren't going in, but I was shooting open ones," Williams said. "They'll fall."

JT Toppin then scored to start overtime and give Texas Tech its first lead since the opening minutes. It went back and forth from there, with D.J. Wagner tying it for Arkansas with 34 seconds left.

Williams then scored down low to give Texas Tech the lead and Wagner's last shot hit the front rim, sending the Red Raiders into a wild celebration at midcourt as Williams pointed to the crowd.

"If we would've just rolled over and let them beat us by 30, season would've been over, and none of us wanted that," Williams said.

Calipari could only walk off the court with pursed lips and a sigh as his first season at Arkansas ended in heartbreak after he fell just short of being the first coach to take four schools to the Elite Eight.

Thursday's loss marked the largest blown lead in the NCAA tournament by a Calipari-led team.

"We're all disappointed here," Calipari said. "But I told them, there's nothing them individually or my team could do to disappoint me because of what they've done this year. I'm so proud of them."

Anderson scored 22 points to lead Texas Tech, while Toppin and Williams added 20 apiece.

Johnell Davis scored 30 points for the Razorbacks and Karter Knox added 20.

ESPN Research and The Associated Press contributed to this report.