Valdes scored Hawaii's final 13 points of the first half. But Patrick Ball kept UH-Hilo in it with two 3-pointers in the final 1:17, including one just before the halftime buzzer, to pull the Vulcans to 44-33.
Valdes was 10-of-12 shooting in the first half and Ball had 13 points for UH-Hilo.
Hawaii went on a 12-0 run midway through the second half, with six points from Isaac Fleming, to extend its lead to 63-40.
Fleming finished with 17 points, six rebounds and seven assists for Hawaii (6-1), which has only lost to Texas Tech on the road.
UH-Hilo, a Division II member, was led by Ball's 20 points. The Vulcans turned it over 23 times and were outrebounded 43-31.