Cameron Clark scored 14 and Jordan Woodard contributed 10 points and eight assists for the Sooners (14-4, 3-2 Big-12).
Woodard's free throw with 9.1 seconds remaining gave Oklahoma a two-point lead, and the Sooners held on for the win when Royce O'Neale's jumper from the left wing came too late to the beat the buzzer.
Baylor (13-4, 1-3) got 16 points from Kenny Chery in its first home loss of the season.
Isaiah Austin netted 12 points and Cory Jefferson added 11 for the Bears.
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