Colorado State (3-0) shot 49 percent from the floor (26 of 53) and was 8 of 19 (42 percent) from beyond the arc. Joe De Ciman added 15 points for the Rams, while Stanton Kidd had 14 points and eight rebounds and J.J. Avila scored 14 points.
Mercer (2-2) was led by Darious Moten with 14 points and seven boards while Jibri Bryan added 12 points.
Colorado State raced out to a 13-3 lead, including a trey by Bejarano, en route to a 40-30 halftime advantage. But Bryan drilled a 3-pointer to open the second half and Moten's dunk cut the CSU lead to five less than a minute in.
But a 13-6 run midway through the frame extended Colorado State's lead to 59-41 and the Rams cruised.