Cousins, a sophomore guard, scored 17 points and made two free throws to give the Sooners at 62-61 lead with 1:30 remaining in the game after they had trailed all of the second half.
The former Knights star made one of two free throws with 26 seconds remaining for a 66-63 Sooners lead but North Dakota recovered to tie the game at 70-70 to get to overtime.
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