Terpstra finished with 18 points and nine rebounds and Mauro's 3 with 3:07 left all but iced it for the Storm (10-7, 5-1 Iowa Conference), who closed the game on a 17-6 run to win their fifth straight.
Kailey Kladivo came off the bench to score 18 points to lead the Knights (8-9, 2-4), who lost their 14th straight game against the Storm at Cowles Fieldhouse.
Mauro finished with 12 points on 3-for-4 shooting from beyond the arch, saving her biggest 3 for last.
Simpson led 61-58 with 3:31 left when Whitney Van Wyk found Mauro alone on the left wing. Mauro obliged the find by hitting her third triple of the game, giving Simpson its largest lead of the second half to that point.
Prior to Mauro's 3, neither team could muster more than a four-point lead in the final 20 minutes.
Van Wyk started Simpson's tear when she banked a runner in the lane with 4:01 left for a 59-58 lead. Terpstra hit two free throws before Mauro's 3 and Markayla Mahr added a pair of free throws to make it 66-58 with 2:22 left, capping a 9-0 run by the Storm.
Simpson returns to action Wednesday, Jan. 29 when it travels to Dubuque for a 6 p.m. tip. The Spartans (11-6, 4-2) allowed the Storm to move into sole possession of second place in the league with a 72-64 loss at conference-leading Loras on Saturday.