Cincinnati survived the Big East quarterfinals with a double-overtime 72-70 win over No. 14 Georgetown, Louisville took out ninth-ranked Marquette 84-71 and Notre Dame escaped with a 57-53 overtime decision over South Florida.
Connecticut, which had won 13 consecutive post-season games, let a lead slip away late against the Orange, who improved to 31-1 for the season and are almost certain to receive a No. 1 seed in the NCAA Tournament.
The Huskies won five games in five days at last year's Big East tourney, and then won six in a row en route to the NCAA title. Connecticut captured the first two games of this year's tournament before falling to Syracuse.
Connecticut led by eight in the second half and still had a chance when Andre Drummond scored on a layup with 9 seconds left to bring the Huskies within one. Waiters, however, broke free for the dunk that sealed the victory and put Syracuse in Friday's semifinals against Cincinnati.
Waiters scored 18 points and James Southerland had 10 of Syracuse's final 15. Shabazz Napier led Connecticut (20-13) with 15.
Cincinnati (23-9) won its thriller against Georgetown on Cashmere Wright's shot with 9 seconds remaining in the second overtime.
Yancy Gates had a short shot with 41 seconds to go that put Cincinnati ahead 70-68 in the second extra period. Henry Sims answered with a jump shot for Georgetown, but Wright's final field goal broke the tie.
Gates led all scorers with 23 points while Sims has 22 points and 15 rebounds for Georgetown. The Hoyas (23-8) managed just two field goals over the last 10 1/2 minutes of regulation but the second -- by Otto Porter -- forced the first overtime at 54-54.
Louisville (24-9) forced 26 Marquette turnovers in its victory and got 20 points from Kyle Kuric. Marquette (25-7) came no closer than four points in the second half after trailing by 10 at the break.
Notre Dame's Pat Connaughton brought about an overtime period by making 1-of-2 free throws with 26 seconds left in regulation and his two foul shots in the final second of the extra period clinched the win over South Florida.
Both Connaughton and Jerian Grant had 12 points for the Fighting Irish (22-10), who dug themselves out of an early 12-point hole.
Victor Rudd paced South Florida (20-13) with 16 points.