Yeager made 11 of 17 shots from the field, including 6 of 11 from 3-point range, for the Titans (12-11, 5-6 Big West), who shot 65.4 percent (17 for 26) in the second half to overcome a 40-29 deficit at the break.
Kwame Vaughn had 13 points for Cal State Fullerton.
Chris Patton scored 36 points on 14 of 16 shooting for the Highlanders (5-18, 2-9).
The Titans made 8 of 14 3-point attempts in the second half. Yeager's shot from behind the arc gave Cal State Fullerton the lead for good, with 9:20 remaining.
Guard Naz Mitrou-Long, whose 2015-16 season ended in December due to hip problems, has been granted a hardship waiver for the coming season, Iowa State said.
As the Sooners look to life without superstar Buddy Hield and his sidekicks, it's clear their unseasoned players will need to grow up fast.
The Central Intercollegiate Athletic Association says it won't move its headquarters, its basketball tournament or other conference championships from North Carolina, despite