Marc Sonnen scored 15 points for the Panthers (20-13), who play at Drexel in the second round. The Dragons advanced with an 81-56 win over Central Florida.
Ronald Roberts Jr. tied the game for the Hawks (20-14) on a thunderous dunk with 7 seconds left to bring them back after they trailed most of the second half.
But Roberts fouled Tuttle with the game tied at 65. Hawks coach Phil Martelli pounded the scorer's table in frustration. Tuttle made the first and appeared to try and miss the second on purpose, but the ball rattled around and in for a 67-65 lead.
The Hawks turned the ball over on their last possession.
Carl Jones scored 24 points and C.J. Aiken had 16 for the Hawks. Halil Kanacevic grabbed 12 rebounds.