Why was Mariano Rivera's Cutter so Good?

File:Mariano Rivera's cutter grip traced onto ball for Roy Halladay at Baseball Hall of Fame.jpg - Wikipedia

Mariano Saves - Sports Illustrated Vault

Elliott: Rivera had gentle touch, with his cutter, with fans — Canadian Baseball Network

Mariano Rivera selected to Baseball HOF by unanimous decision - Sports Collectors Digest

Mariano Rivera New York Yankees Cutter Bobblehead FOCO

Yankees legend Mariano Rivera talks cutter, playoff pressure, mound visits and more

Fame hasn't changed Yankees' Mariano Rivera

For as much as we knock SDS for servers, they deserve credit for attention to detail. I watched an interview with Mariano Rivera. This is his cutter grip. Index finger slightly off

Prospect Retrospective: Mariano Rivera, RHP, New York Yankees - Minor League Ball

Case Closed: Reflecting On Mariano Rivera's Impact On Baseball — College Baseball, MLB Draft, Prospects - Baseball America

Mariano Rivera's Baseball Hall of Fame induction in Cooperstown gives the nod to a man known best for fear