O'Neill has transformed the Black Cats' fortunes since replacing Steve Bruce at the Stadium of Light.
"At man-management he is the best there is, incredible," said ESPN football analyst Savage, who will be working with the broadcaster as part of their FA Cup third-round coverage this weekend.
"He knows players. He knew he could hammer me and I'd come out and want to prove him wrong. Other players would go into their shell if he did that."