World number seven Roger Federer believes that he only has himself to blame for his surprise exit at the US Open.
The Swiss was dumped out in the fourth round at Flushing Meadows after a 7-6 6-3 6-4 defeat to Tommy Robredo on Monday.
Despite the impressive form of the Spaniard, Federer feels that he largely contributed to his own downfall.
"I kind of feel like I beat myself, without taking any credit away from Tommy. Clearly he was making sure he was making many balls. It was up to me to make the difference and I couldn't," Federer told reporters.
"I kind of self-destructed, which is very disappointing, especially on a quicker court. Your serve helps you out. You're going to make the difference somewhere.
"I just couldn't do it. It was a frustrating performance."
Federer has won 17 Grand Slam titles during his career.