#3 1991 vs #6 2001
Starters and Bench
1991 is one of those sentimental favorite teams. 1991 was the first UNC team since the 1982 NCAA Champions to make it to the Final Four. And it could not come at a better time. After UNC won the title in 1982, the Tar Heels ended up in the Elite Eight four times but could not get over the hump. Couple that with the 1984 team falling to Indiana in one of those fluke NCAA Tournament upsets, the frustration level among Tar Heel fans was high. Enter the 1991 team coming on the heels of a down season in 1990. UNC was an experienced team with a trio of seniors buffered by(at the time) the best recruiting class of all time. Toss Hubert Davis and George Lynch into the mix and you had a solid team that handed Duke a 20 point loss in the ACC Championship game.
So that team going against the 2001 which was the complete opposite in many ways. Whereas 1991 was the picture of a team coming together with the right mix of experience and talent versus a team that was plenty talented but fell apart at the seams. The 1991 team ushered in an era of frequent Final Four trips, a second national title for Dean Smith. The 2001 team led to 2002 and we don't talk about 2002.
All of this is to say 1991 probably wins just on cohesion alone and also because Dean Smith versus Matt Doherty isn't any sort of contest.