Brown hit a trio of three-pointers in a three-minute span to fuel a late 13-2 run as the Tigers won their first NCAA Tournament game since 2010 and they will face 15th-seed Princeton in the second round.
"He's our MVP. I can tell you that", said head coach Dennis Gates. "Ultimately when he started making some shots in the second half, he immediately made eye contact.
"He said he's here. I said 'yes you are. We can see.'"
D'Moi Hodge led seventh-seed Missouri with 23 points and Brown added 19 as the Tigers improve to 25-9. Utah State (26-9) had four players in double figures, led by Taylor Funk's 16.
The Aggies shot a season-worst 4 of 24 from behind the three-point arc and committed 15 turnovers, which led to 23 Missouri points.
Story of the game
Both teams were cold from beyond the arc, Utah State failing to connect on their first six three-point attempts, but Brown and Noah Carter were able to create scoring opportunities by penetrating the paint.
The Tigers led 18-12 with 11:58 left in the first half as Missouri's defense forced eight first-half turnovers by Utah State and Hodge set the tone with a couple of early steals and three-pointers.
Utah State pulled to within 28-25 thanks to a 4:04 field goal drought by the Tigers and some layups towards the end of the half by Steven Ashworth allowed the Aggies to stay within striking distance at 35-31 going into halftime.
Ashworth and Funk connected on threes early in the second half to put Utah State in front and they forced Missouri into uncharacteristic mistakes at both ends of the floor.
After trading buckets that saw the Aggies lead 49-47 with 10:54 left, Brown took matters into his own hands, scoring 12 straight points and Hodge followed with a three to make it 62-53 and forcing Utah State head coach Ryan Odom to call a timeout.
"We don't blink", Brown said. "We felt them getting the momentum, but we couldn't show that. If we would have showed that, things would have went a lot different."
Hodge would bury another triple to push the advantage up to 11, Missouri's largest of the game and they closed out the game at the free throw line.