Muhammad and Williams came up big for the Spartans (2-8) after a seesaw first half that saw the tiny, independent Firebirds (1-10) battle through nine lead changes, six ties and trail just 33-30 at halftime. Williams scored seven points on his first three shots after halftime, and Muhammad added the next five as the Spartans broke away to a 10-point lead, and Firebird leader D'Vaughn Mann picked up his third and fourth fouls.
Saint Katherine's had one more rally, closing to 58-55 on a 10-3 run before Mann fouled out with 6:24 remaining.
The Spartans closed out on a 16-7 run from there.
LeSean Galbreath scored 20 for Saint Katherine, Dante Miller 15.