Trailing 40-12 late in the first half, Tyler Hansbrough, Wayne Ellington and the Tar Heels made a valiant rally, getting as close as five points with nine minutes left, but ran out of steam in their effort to pull off the biggest Final Four comeback ever.
Kansas moved within a win of its first national championship since 1988, the year before Williams began his storied 15-year tenure in Lawrence - one that ended when he jilted Kansas for his alma mater.
The Jayhawks will play Memphis, an earlier 78-63 winner over UCLA, in the title game Monday.
Sherron Collins had two assists, a 3-pointer and a pair of free throws during the decisive stretch that saw the Jayhawks (36-3) pad that five-point lead back to 15 and send the Tar Heels (36-3) into true desperation mode.
Williams stood stoically as the clock ticked down, arms folded, nothing much left he could do. Tears usually come pretty quickly after the final buzzer of the season him, and this game ended one game short of where many thought it might.
Still, at game's end he walked to the Kansas bench and shook every player's hand, hugging many of them.
It was Bill Self who replaced Williams after the coach famously bolted for his alma mater, and this was the first chance to see them go against each other with their new teams - and on the game's biggest stage.
Hansbrough, the national player of the year, finished with 17 points and nine rebounds - a typically gutsy effort. Ellington led the Heels with 18.
But for all their effort, this game was lost early.
The basket looked as big as the Alamo for the Jayhawks, who made 12 of their first 16 shots and went on an 18-0 run for a 33-10 lead with 9:31 left.
Meanwhile, North Carolina went a stunning 9:03 without a basket and the lead got as large as 40-12. It was around then that none other than Billy Packer, the CBS analyst, said the game was over.
Not so fast.
