In the second OT, Waldow hit a quick layup and Simmons sank a big 3 to give the Gaels a five-point lead with 3:48 left, which they protected down the stretch.
Saint Mary's (19-6, 11-3 West Coast Conference) blew an 11-point halftime lead but got a 3-pointer from Aaron Bright with 13 seconds left in regulation to tie it at 56 and force overtime. Neither team scored during the first overtime until Bright, who finished with 15 points, sank a bucket with 1:14 left. San Diego tied it at 58 with a jumper from Duda Sanadze, who was fouled but missed the free throw.
Johnny Dee led San Diego (14-13, 7-8) with 21 points and Sanadze had 12.