The Huskies (1-7) were up 47-46 on a Pedro Castro 3-pointer just over five minutes into the second half and trailed 58-54 after Darius Lee made a pair of free throws at 12:04.
Elijah Harkless made two free throws to start the run before Iwuakor had back-to-back dunks and a jumper. After Alondes Williams scored, Iwuakor added another jumper before De'Vion Harmon's layup made it 72-54 with 6:47 to play.
Houston Baptist missed eight-straight shots while the Sooners went 6 of 8. The Sooners shot 49% despite going 5 of 23 from 3-point range.
Harmon and Manek made the last two baskets of the first half to give Oklahoma a 38-35 lead.