"I was just trying to beat the clock, as fast as I can," Brown said.
Ford said Brown — who went 4-of-17 from the field — made the right play.
"I was hoping he would get to the rim, because so many players pull up," Ford said. "So many players don't think they have enough time. But you've got more time than you think you do."
Brown intercepted a desperation inbounds pass by Baylor's Jacob Neubert to end the game.
Drew said he had no problem with Walton's shot that was blocked.
"The look was good," Drew said. "I think we just gave them a little too much time."
The Bears had won three straight and eight of their last 12 games against Oklahoma State before Wednesday.
The Cowboys started 1-of-13 from the field before rallying for a 24-22 halftime lead. They trailed 32-28 when Le'Bryan Nash, who had gone scoreless in the first half, made his second basket in the first three minutes after halftime.
That ignited a 12-2 run, capped by an alley-oop dunk, with Smart lobbing to Brown with 13:40 left to make it 40-34 and igniting a roar from the Gallagher-Iba Arena crowd.
Oklahoma State extended its lead to 54-40 on a 3-pointer by Phil Forte with 7:40 left — the Cowboys' first of the game. But Jackson had two 3s and a layup during a 17-3 run by the Bears. Cory Jefferson hit a lay-in with 1:52 left to tie the game at 57.
Smart, who went 4-of-21 from the field, hit a 6-foot leaner with 1:23 left to put the Cowboys back ahead, but Jackson made two free throws with 6.5 seconds left. The Cowboys had a chance to win at the regulation buzzer, but Brown missed a 3-point attempt from the left wing.
Jackson opened the overtime with a pair of 3-pointers and the Bears were up 67-64 after a dunk by Jefferson with 1:46 left. Forte's 3-pointer with 1:11 left pulled the Cowboys even.
Jackson dribbled the ball out of bounds with 43.5 seconds left, but Smart missed a contested shot from underneath the basket with 15 seconds left, setting the stage for the final sequence.
Nash scored 10 points and Cobbins had nine points, 13 rebounds and two blocks for the Cowboys. Jefferson added 18 points for Baylor while Isaiah Austin had 12 rebounds go to with seven points — more than seven below his scoring average.