The Tigers (28-3) trailed by as much as 12 by didn't let up on the Crusaders (27-6) and imposing center Josh Kosin (25 points, 11 rebounds).
But Beaver Falls took advantage late with Kosin and teammate Casey Gaughan (10 points) in foul trouble.
Beaver Falls finally took its first lead midway through the fourth quarter. Mason (14 points) hit two 3s in the final four minutes, and the Tigers got their last seven points at the foul line. Four Tigers scored in double figures.
Kosin's foul trouble disrupted Holy Cross down the stretch.