The Spartans led 14-6 after one quarter, 22-19 at halftime and 38-26 after three.
Saginaw Nouvel surged ahead and stole the victory in the fourth quarter, shooting 80 percent from the floor, including four 3-pointers.
Foul trouble was an issue for the Spartans down the stretch, and they couldn’t find a way to offset the Panthers’ scoring barrage.
Austin Tyndal scored 10 points to lead the Spartans. Ryan Mount added nine and Jeffery Carrier had eight. Miguel Monroy led the Panthers with 16 points while Christian Hagara netted eight.
Mason County Central wrapped up the season at 12-12.
Saginaw Nouvel improved to 13-11 and advanced to Wednesday’s regional final.