Roger Federer enjoys being one of the pre-tournament favorites, having just won the Cincinnati Masters. If he wins, it will be his 6th U.S. Open title, the most in the Open Era, and rank him with only Bill Tilden who won 6 in a row in an earlier era (1920s), almost a century ago. I think that 6 U.S. Open titles in the Open Era (if Federer can do it) will be the most unbreakable of Federer's monumental records in tennis. Why? Because the U.S. Open is widely considered the most difficult Grand Slam to win, in part because it is the only slam to sport a tiebreak in any 5th set. Regardless, I think that students of tennis will be studying the tennis game of Federer (as they did for Tilden's game in an earlier era) for a long time to come. Good luck, Fed.