Roger Federer easily advances to fourth round

      Five time U.S. Open champ Roger Federer won again in straight sets, beating Paul Henri Mathieu of France, 6-4, 6-3, 6-3, in in the third round Saturday.

       Federer, the No. 2 seed,   had 13 aces in the match against the 109th-ranked Mathieu.

       Federer won here five years in a row before losing to Juan Carlos del Potro in 2009

       Barbara Barker, aka meanbarb on twitter