John Isner hit 13 aces in his second round match then struck 17 aces in his third
round match; with both matches straight set wins at 68 minutes long each.
The American, who received a bye in the first round, is ranked 15th on the ATP Tour.
The 25 year old Donald Young, ranked 46th, is the second highest ranked American professional tennis player.
In 2009 in the third round, Isner; then ranked number 55th and unseeded, upset the then highest ranked American Andy Roddick
in a stunning five set match.
However the American is 2-5 head to head versus the US Open's top seed and favorite Novak Djokovic of Serbia.
Isner, whose best US Open result was a 2011 quarterfinal finish, is seeded 13th at tennis' last grand slam of this year which
begins Monday in New York.