The Trojans (1-1), who shot 54.9 percent from the field, jumped out to an early 24-8 lead fueled by a layup and a trio of 3-pointers from Williams.
Troy surged further ahead and led by as many as 33 in the first half, coasting to a 59-27 lead at the break.
The Panthers were just 24 of 77 on field goal attempts, struggling to keep pace with the Trojan's shooting performance.
Williams hit five total 3-pointers, grabbed eight rebounds and dished out a game-high five assists. Josh Warren hauled in a game-high 11 rebounds and scored eight points.
Mississippi State freshman guard Malik Newman will withdraw from the NBA draft, but sources told ESPN he might explore other opportunities besides returning to Mississippi State.
Seton Hall sophomore Isaiah Whitehead will stay in the NBA draft and not return for his junior season.
Washington State's trio of Josh Hawkinson, Conor Clifford and Ike Iroegbu have withdrawn from the NBA draft and will play their senior season with the Cougars.