NEW YORK -- Langston Galloway made a go-ahead 3 with 17.9 seconds left and finished with 31 points as St. Joseph's beat Dayton 70-67 in the quarterfinals of the Atlantic 10 tournament on Friday.
Fourth-seeded St. Joseph's (22-9) completed a three-game sweep of the Flyers (23-10) in a game matching teams hoping to land, though far from locks to receive, at-large NCAA tournament bids.
Matt Kavanaugh made a baseline jumper to give fifth-seeded Dayton a 67-66 lead with 40 seconds left.
Galloway, who beat the Flyers in the regular season by banking in a 3 in the closing seconds, cleared some space at the top of the key with his left forearm and nailed a 3 over Kyle Davis to put the Hawks (22-9) up 69-67.
St. Joe's advances to the semifinals Saturday to face St. Bonaventure, which upset Saint Louis in the day's first game at Barclays Center in Brooklyn.
Dayton entered the quarterfinals having won four straight and 10 of 11 overall to make a push for an NCAA at-large bid. The Flyers last made the NCAA tournament in 2009.
St. Joseph's lost its last two regular-season games to make the road to the NCAA tournament a little less clear. The Hawks and longtime coach Phil Martelli haven't been to the NCAAs since 2008.
The lead never got beyond six points for either team. Every mini-run was answered with another.
Ronald Roberts put St. Joe's up 64-60 with 5:26 left, skying high over a defender to slam back a missed 3-pointer and leaving the backboard shaking. When Galloway added a couple of free throws moments later it looked as if, with the six-point lead, the Hawks had things under control.
Sibert hit a 3 and Kavanaugh took advantage of foul trouble on St. Joe's versatile big man Halil Kanacevic to score down low and make it 66-65 with 2:20 left.