The Buffaloes (2-0) trailed 37-30 with 14 minutes left when Xavier Johnson got the surge started with 3-pointer. Spencer Dinwiddie put Colorado ahead with a three-pointer. Johnson added a pair of foul shots and Andre Roberson made a basket for a 43-37 lead.
Johnson finished with 15 points, Josh Scott 13 and Dinwiddie 12 for Colorado. Roberson, third in the country in rebounds last season, had 14 boards to go with six points.
Vee Sanford led Dayton (1-1) with 13 points. Last year's leading scorer for the Flyers, Kevin Dillard, scored all of his 10 points in the second half.