Georgetown shot 71% from the field in the first half and led by as many as 18 points early on, mostly behind Austin Freeman and Chris Wright. But Michael Dixon, Marcus Denmon and Ricardo Ratliffe led a Mizzou charge and cut the lead to seven at half.
The teams traded baskets early on in the second half until Mizzou's pressure defense started to rattle the Hoyas as G'Town's shots started catching iron instead of net.
Mizzou took their first lead of the game at the 8:24 mark of the second half on a three ball by Denmon as the teams again started swapping baskets.
With Mizzou up four, Dixon committed a foul 30 feet from the hoop which sent Wright to the line, sinking both the Hoyas trailed by 2. After Dixon made one of two free throws with 14 seconds remaining, Hollis Thompson heaved a desperation three that miss badly. Trying to grab the rebound and secure the victory, Kim English followed the shot out of bounds, and in trying to save it threw it Jason Clark who found an open Wright in time to nail the game tying shot with 0.3 seconds left.
Overtime was all Georgetown as the Hoyas hit three after three and Mizzou couldn't find the bottom of the net.
The Hoyas ended the game with four players in double figures, as Freeman scored 31, Clark 26, Wright 21 and Henry Sims 10. Wright also led the Hoyas with 10 rebounds.
Mizzou found five guys with double figure scoring as Denmon scored 27, Ratliffe 22, Dixon 17, English 11 and Laurence Bowers 10.
Georgetown didn't miss a free throw all night, going 18-18 and ended the game hitting 15 3s to Mizzou's 7.