The Penguins (10-14 overall and 4-7 in the Horizon League) trailed by five points at halftime before Oakland (17-7 and 7-4) used a spurt at the outset of the second half to gain control.
On the night, Santiago was 11-of-18 from the field, with a pair of 3-pointers and two free throws to finish with a career-best 26 points. His previous high total was 23 against Canisius which he had back in November.
Haygood had a career night with 21 points on 9-of-11 shooting and three free throws. His previous career best scoring outing was 11, which came on two occasions. He also had a career-high nine rebounds in the contest, besting his previous of seven.
For the game the duo was 20-of-29 from the field and in the first half they combined for 27 of YSU's 37 points.
Santiago opened the game by scoring the Penguins' first nine points and was 6-of-11 from the field. Hagood came off the bench to make all six of his field goal attempts and added a pair of free throws to finish with 14 points in the first 20 minutes.
Both teams shot well with Oakland making 17-of-30 attempts (56.7 percent) and YSU connecting on 16-of-34 shots (47.1 percent).
The Penguins couldn't connect to open the second half and the Golden Grizzlies took advantage opening the frame on a 24-9 run in the first seven minutes to go on top 66-46 following a 3-pointer by Nick Daniels. The closest the Guins could get the remainder of the contest was 73-60 following a mini 7-0 run midway through the second half.
For the game, YSU shot 46.3 percent (31-of-67) while Oakland made 32-of-63 shots (50.8). The Golden Grizzlies were impressive from the line making all 18 attempts.
Scoring in double figures also for the Penguins was Cameron Morse who had 12 points. Four players finished in double digits for the Golden Grizzlies with Jalen Hayes scoring a team-best 21 points.
The Penguins are back in action on Saturday night when they play host to Detroit. Tipoff at the Beeghly Center is set for 7 p.m.