Andre Iguodala scored 25 points, Williams had 19 and Elton Brand contributed season highs of 19 points, 11 rebounds and six blocked shots for the Sixers, who snapped a two-game losing streak. Rodney Carney had 10 points for Philadelphia.
With the score tied at 84, Boris Diaw missed a baseline jumper and Iguodala gathered the rebound. He dribbled to midcourt and passed to Williams for the layup on the fast break.
The Bobcats never got off a shot on their final possession.