McDermott scored 39 points with nine rebounds and Manigat scored 11 as No. 13 Creighton improved to 16-1 with the victory. The team's only loss this season came against Boise State in November.
McDermott, a Player of the Year candidate, came into the match averaging nearly 23 points per game. He shot 15-of-19 on Friday, including 3-for-4 from three-point range. His previous season-high was 34 points against the Cal Bears on Dec. 15.
Creighton shot 57 percent from the floor and 53 percent from three-point range. Missouri State (5-13) shot just 40 percent for the game. Keith Pickens scored 11 points and Gavin Thurman and Anthony Downing had 10 points each for the Bears.
The only ranked opponent left on Creighton's schedule is conference foe Wichita State, currently ranked No. 23.