IPFW senior forward Frank Gaines led five Mastodons in double figures with 17 points.
Luis Jacobo added 15 in the victory, while Joe Reed (14), Joe Edwards (11), and Mario Hines (10) also produced.
In all, 18 of IPFW's 27 baskets were assisted, as Pierre Bland and Jacobo each dished out four.
Jacobo also grabbed an IPFW-career-high nine rebounds, as IPFW outrebounded Oakland 35 to 33.
IPFW jumped ahead quickly, leading 12-7 after a Gaines three-point basket; however, the Grizzlies ran off a 16-5 run to lead by six, at 23-17 with 10:59 to play.
The Mastodons, facing their biggest deficit of the game, immediately ran off eight straight points, capped by a pair of Gaines free throws, and a 19-2 overall run that gave IPFW a 36-25 advantage with 5:10 to play after a Hines lay-in.
That Hines basket would be the last IPFW would score in the period, with Oakland running off eight straight to close the gap to three at the break.
Neither team could get an offensive foothold early in the second half, with the margin fluctuating between one and six points in favor of IPFW for the first 14 minutes of the second half, before Oakland tied the game at 62.
A possession later, the Grizzlies took their first lead of the second half on a lay-up at 64-62 with 5:30 left in the game.
The Grizzlies led by one at 65-64 with 3:56 left in the game. However, the Mastodon defense dug its ground and held Oakland scoreless for a 3:25 span, at which the Dons scored a dozen, to push ahead by 11 at 76-65 after a pair of Gaines free throws.
Oakland outscored IPFW 6-1 over the final 31 seconds, but the damage had been done in the IPFW win.
IPFW went 27-of-62 from the field (43.5 percent), 8-of-23 (34.8 percent) on three-point shots, and 15-of-21 (71.4 percent) from the charity stripe.
Oakland hit 47.2 percent (25-of-53) of its shots from the field, 5-of-20 (25.0 percent) from long range, and 16-of-29 (55.2 percent) on free throws.
The Mastodons will host Bowling Green on Saturday at 7 p.m. at the Coliseum in the Ramada Worldwide Bracketbuster game.