What Major League Baseball pitcher has the most career postseason shutouts?

Christy Mathewson, Hall of Fame pitcher with the New York Giants, is MLB's all time postseason shutout leader with 4. After Josh Beckett's shutout in Game 1 of the 2007 ALDS series with the Angels, he is tied for second place all time with Whitey Ford and Mordecai (Three Finger) Brown with 3 postseason shutouts.