Joel Awich hit a 3-pointer to give Cal Poly (8-10, 4-1 Big West) a 58-53 lead with 3:05 remaining, but it turned out to be the last time the Mustangs scored.
However, Cal Poly limited the Titans (6-12, 1-3) to just a point in the final 3 1/2 minutes to hold on for the win. Alex Harris missed a jumper which would have tied the game with 2 seconds left for Cal State Fullerton.
Cal Poly scored 11 straight points early on, racing to a 17-5 lead. The Mustangs are off to its best Big West start in its program's 18 years as a conference member.
Michael Williams led Cal State-Fullerton with 20 points.
Mike Brey is looking at former Notre Dame players to fill two assistant jobs that have opened up with the departures of Martin Ingelsby and Anthony Solomon.
Purdue's 2016-17 prospects got a jolt Wednesday when forward Caleb Swanigan announced he will return for his sophomore season.
Clemson's Jaron Blossomgame says he is withdrawing from the NBA draft and returning to school for a final season.