http://bit.ly/2AbEv8g How the Math Behind Roger Federer’s Clay Season Helps His World Ranking Italian Open (Tennis), French Open (Tennis), Tennis Just by playing in clay-court tournaments, Federer has earned ATP ranking points that fended off his young challengers for the No. 3 spot. STUART MILLER http://bit.ly/2W4UqCk May 25, 2019 at 05:30AM