BUFFALO, N.Y. — THE University of Dayton is to be reckoned with.Dyshawn Pierre scored 14 points and Jordan Sibert, held scoreless in the first half, hit a key 3-pointer with 47.7 seconds left as Dayton stunned Syracuse 55-53 Saturday night to earn a spot in Sweet 16 for the first time in three decades.Syracuse was poised to pull out another close victory, but Tyler Ennis missed two jumpers that would have given the Orange the lead in the final seconds.Dayton (25-10), the 11th seed in the South Regional, advances to the regional semifinals next week and will play Kansas or Stanford.The third-seeded Orange (28-6), who finished second in their first year in the Atlantic Coast Conference, struggled all game against the swarming Dayton defense, missing all 10 attempts from beyond the arc, while the Flyers hit seven times from long range.After Sibert stepped out of bounds with 14 seconds left and Dayton up by one, Ennis took a jumper from just inside the 3-point line instead of driving the lane as he had all night. The standout freshman finished with 19 points on 7-of-21 shooting, including 0-5 on 3-pointers.Syracuse fouled Pierre and he made one free throw. Ennis rushed down court and missed the potentially winning 3 as the buzzer sounded.Sibert finished with 10 points and Sanford had eight.It was another close win for Dayton after beating in-state rival Ohio State 60-59 Thursday.