Novak Djokovic admitted he had lost to the better man after going down in straight sets to Roger Federer in the US Open final.
The third seeded Serbian led both of the opening two sets before allowing Federer to force tie-breaks, both of which were won by the Swiss player.
Djokovic conceded his first appearance in the final at Flushing Meadows had been a learning experience.
"I was in a good position, everything was good and then suddenly I just started making these unforced errors, which are really not understandable," he said.
"And then I was quite nervous. There was a lot of pressure and I knew I had to make some shots.
"Obviously that was a mistake because I just needed to calm down and wait for my chances, which I didn't."
Djokovic was gracious in defeat, giving a warm tribute to Federer's achievement of winning the US Open for the fourth year in a row.
"I'd like to congratulate Roger," he added. "Once again he has shown that he is the best and he deserved to win. He was the better player.
"I think I was mentally weaker on important points and he was mentally stronger. It was my mistake and my weakness.
"I had quite a lot of pressure but I enjoyed it. It was an amazing experience for me.
"But it's normal. It's a bad day and in general, looking at the whole year I've been performing really well."

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