South Dakota (7-9, 2-0 Summit League) outscored IUPUI 22-8 in the final 11:24 of the game after IUPUI had taken a 49-47 lead.
A Bos 3-pointer put the Coyotes up 50-49, and IUPUI (5-15, 0-3) made just two field goals the rest of the way as South Dakota continued to pull away.
Boss scored 21, including 13 in the second half. Gruis had 18, with 12 coming in the second half.
The Jaguars had a 33-32 lead at halftime before shooting just 29.2 percent after the break. The game had 11 lead changes and seven ties before South Dakota took charge in the second half.