PIERSON — The Taylor Wildcats took down Williston in three straight sets (25-18, 26-24, 25-21) on Tuesday to advance to the Class 1A regional semifinals.   Led by a 20-kill night from senior Brittany Cowart, the Wildcats (21-3) defeated the Red Devils for the second time in two weeks to improve their winning streak to 11 games.   Despite the sweep, it was far from a worry-free night for head coach Tanya Ramos.