Instead, Paige answered a shot for the lead from Terry Rozier in the final minute, then the Tar Heels survived two shots for the win - a 3-pointer from Wayne Blackshear and an off-balance stickback attempt from Rozier - on the wild final-play sequence.
Paige, a preseason all-American mired in a slow start to the season, finished with 10 points on 4-for-12 shooting and shook off a right ankle injury that sidelined him briefly after halftime.
Rozier scored 25 points to lead the Cardinals (14-2, 2-1), while Chris Jones scored 19 in a strong performance from Louisville's backcourt. But the Tar Heels contained Montrezl Harrell, Paige's fellow preseason Associated Press all-American who finished with nine points and five rebounds in 38 minutes.
Brice Johnson led the defensive effort on Harrell and finished with a double-double (11 points, 11 rebounds). He also hit a huge shot, taking a pass from Paige and scoring in the lane with 38.1 seconds left to give UNC a 70-69 lead - the Tar Heels' first of the second half.
It didn't look like a very likely outcome considering the way Louisville dominated the start of the second half. The Cardinals made 13 of their first 20 shots - coming against a team that had held 13 of its first 15 opponents to lower than 40 percent shooting - and led 63-50 on Blackshear's 3 with 8:43 left.
But the Cardinals cooled off and had a couple of turnovers that helped the Tar Heels find some momentum that recharged the home crowd and helped them inch their way back into the game.
UNC closed within 69-66 on Johnson's basket, then closed the gap to one when J.P. Tokoto tipped in his own miss near the 2-minute mark.
Louisville: This was only the second trip to Chapel Hill for Louisville, the other being a loss in December 1998. ... Blackshear finished with 10 points. ... Louisville shot 48 percent, including 50 percent after halftime, but missed 8 of its final 10 shots.
UNC: This was UNC's sixth game against a Top 25 opponent. It improved to 4-2 in those games. ... UNC shot 43 percent. ... The Tar Heels took a 40-30 rebounding advantage, including 17-9 on the offensive glass that led to a 17-6 edge in second-chance points.
UNC heads to North Carolina State on Wednesday.