Milwaukee's Cody Wichmann converted two free throws with 2 seconds left, but Oral Roberts' Denell Henderson sealed it with two of his own.
Obi Emegano scored 20 for Oral Roberts (2-3) and Billbury finished with 19 points, 11 rebounds and six assists.
Henderson's three-point play midway through the second half gave Oral Roberts a 15-point lead.
Steve McWhorter scored 21 points for Milwaukee (2-4) and JeVon Lyle had nine.
McWhorter made two 3-pointers during a 13-4 run to pull Milwaukee within 54-48 and made another at the 2:59 mark to cut it to 60-57. Lyle made two free throws to tie the game at 64 with 29 seconds left - the closest Milwaukee had been since it was tied at 20.