IPFW was led by Haley Seibert, who liut up the Coyotes for a career-best 35 points. The junior connected on 12-of-18 from the floor, including a career-best seven three-pointers.
Amanda Hyde added 23 points in the win, as she connected on 11-of-12 at the free throw line, while dishing out a game-high six assists and nabbing five rebounds.
Rachel Rinehart came off the bench to score 12 points for the Dons, while Rachel Mauk went for eight points.
Rebecca Bruner led IPFW on the glass with six rebounds and former South Side High School standout Ariana Simmons grabbed a game-high four steals.
South Dakota jumped out to an early advantage, taking its largest lead of the game 13-4 four minutes into the game. Seibert scored 10 straight points for the Dons as they rallied, trailing by three points following back-to-back baskets by Simmons and Rinehart.
After a pair of free throws by Seibert, Rinehart connected on a pair free throws before knocking down a three-pointer from the right wing to tie the score 25-25 with under nine minutes to play. Rinehart found Rachel Mauk with a long pass, as Mauk hit the fast break layup, giving IPFW their first lead of the game 27-25.
With South Dakota holding a 42-38 advantage and two minutes to play in the half, Seibert drilled back-to-back three-pointers to give IPFW a 44-43 lead at halftime.
Midway through the second half South Dakota made a 7-0 run to take a 62-61 lead. That would be the final time the Coyotes held the lead as Simmons ended the run with a layup and Seibert followed with her sixth three-pointer of the afternoon.
With the Dons holding a two point lead, the IPFW defense stepped up big, holding the Coyotes to just five points the rest of the game, as the Mastodons outscored South Dakota 21-5 over the last five minutes of the game. During that same stretch the Mastodons were a perfect 7-of-7 from the field and 4-for-4 at the free throw line.
The IPFW offense shot over 50 percent for the second straight game, hitting 31-of-58 (53.4 percent). The 'Dons also connected on 13-of-29 (44.8 percent) from behind the arc and 21-of-24 (87.5 percent) at the charity stripe.
As a team IPFW committed just six turnovers, the fewest since also committing six against North Dakota State on February 9 of last season. The seven three-pointers by Seibert were the most by an IPFW player since Anne Boese hit eight against Butler on November 20, 2011.
IPFW will travel to in-state rival IUPUI Saturday at 3 p.m.