McDermott went 10-of-19 from the field and 8-of-11 from the free-throw line for the Bluejays (6-0), who claimed the championship of the Continental Tire Las Vegas Classic.
Ethan Wragge supplied 13 points for Creighton.
Jahii Carson struck for 30 points, seven assists and four steals, but also turned the ball over five times for the Sun Devils (4-1).
Carrick Felix added 17 points and five boards for Arizona State.
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