McCallum was just 6 of 15 from the field and Calliste was 3 of 12, but the pair combined to go 25 of 27 from the free-throw line. That was the story for the Titans (10-5, 2-0 Horizon League), who shot 37.5 percent from the floor but 90.5 percent from the line.
Juwan Howard Jr. added 16 points for Detroit, which never trailed in the second half but saw the Phoenix (6-9, 0-2) close within 71-68 on Alec Brown's free throws with 3:05 to play. But Doug Anderson's layup and Howard's foul shots pushed the lead back to seven, and McCallum and Calliste went 8 of 9 from the line in the final 1:10 to seal the victory.
Keifer Sykes led Green Bay with 21 points.
Purdue coach Matt Painter says players haven't used the fifth-year graduate transfer rule for its true intent.
The dust has settled after players made their NBA draft decisions. Which college teams won? Which lost? Well, Villanova is pretty happy. USC, meanwhile, might not be as thrilled.
The 2017 recruiting class is short on point guards, with Trevon Duval leading only eight prospects from the ESPN 60 who are still available.