Pitcher with .671 lifetime winning percentage

Today’s question: Name the pitcher with the best won-lost percentage of any hurler with at least with 15 wins against the New York Yankees? Hint (but not a very good one), he was a 20-game winner twice, with a lifetime .671 winning percentage.

Yesterday’s answer: Counting singles, doubles and mixed doubles, tennis great Martina Navratilova has won 359 titles, The most of all time.