After Noah Rubin's final backhand sprayed wide Monday, he shook hands with an opponent who stood a head taller and carried 20 more pounds of muscle.
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"The movement wasn't there, the intensity," Rubin said.
Slam or not, he added, "Juniors is not my dream, it's going pro . . . I have 50 more tournaments after this."
This was to have been a coming-out party of sorts for the Long Islander, who played only doubles here last year.
Since then he's made deep runs at the French Open, Easter Bowl and boys 18s national championships, arriving here as the 14th seed and ranked No. 16 in the world.
Monday he had an opening after two return winners and two double faults from Edmund put him up a break at 3-2 in the first set.
But he followed with a sloppy game of his own and never again threatened, struggling with his serve and Edmund's forehand, a weapon that kept Rubin off-balance and scrambling in rallies.
Rubin's 2012 U.S. Open continues in doubles. He and fellow American Alexios Halebian teamed for a 6-1, 7-5 first-round win over Croatian Franko Miocic and Czech Vaclav Safranek Monday.
Rubin left high school last year to pursue tennis full-time. John McEnroe, an occasional playing partner and mentor, has described his professional potential as "top 50, minimum."