Rotnei Clarke scored 21 points, and Butler advanced at the Atlantic 10 tournament with a 73-67 first-round victory over Dayton on Thursday.
The fifth-seeded Bulldogs will need to win four games in four days if they want a conference tourney title in their first - and perhaps last - season in the A-10.
Clarke shot 6 of 12 from behind the 3-point arc and added five assists. Fellow senior Andrew Smith had 18 points and six rebounds.
Butler was 10 for 24 on 3-point tries, while the Flyers attempted just four. Josh Benson had 18 points to lead 12th-seeeded Dayton (17-14, 7-9).
The Bulldogs (25-7, 11-5) will face fourth-seeded La Salle in Friday's quarterfinals.