Tu Holloway scored 21 points and Kenny Frease had 17 to lead Xavier to a 70-69 win over Dayton on Friday night and advance to the Atlantic 10 Conference tournament semifinals.
Mark Lyons put Xavier up on a layup with 21 seconds remaining to send the third-seeded Musketeers (20-11) into Saturday's semifinal against Saint Louis.
Chris Johnson missed the go-ahead 3-point attempt for Dayton (19-12). Kevin Dillard led the sixth-seeded Flyers with 18 points. Paul Williams and Josh Parker each scored 11.
There was a small fire at Boardwalk Hall that did not disrupt play nor force fans to leave the building. After the building became smoky late in the second half, the public address announcer said the fire had been extinguished and there ''was no cause for alarm.''
Xavier shot 56 percent from the floor (14 of 25) in the second half to rally from a 38-28 halftime deficit.