Trailing by three with 11 seconds left, BU (12-11, 5-5 Patriot League) tied it at 73 with a 3-point play from Eric Fanning, then got a turnover with two seconds to go, setting up Papale's floater to win it. Fanning finished with 16 points and Papale had 10.
Nathan Dieudonne added 12 points and Nick Havener also had 10 for the Terriers, who trailed most of the game but used a 15-2 run midway through the second half to build a 63-51 lead with 8:47 to play.
Lehigh (6-14, 4-5) twice edged back into the lead before BU sealed it.
Tim Kempton led Lehigh with 24 points and 11 rebounds, Jesse Chuku added 14 points and Kyle Leufroy had 13.