A day after giving a speech at the United Nations, Novak Djokovic was back in more familiar surroundings on Saturday, signing autographs and fine-tuning his preparations for the U.S. Open.
The world number one addressed the U.N. General Assembly on Friday as part of the declaration for an International Day of Sport for Development and Peace next year.
"The speech at U.N. yesterday was also something quite incredible for me," he told reporters at Flushing Meadows on Saturday.
"I was blown away by these wonderful opportunities that I got personally to speak at the U.N. in the name of the global family of athletes."
Djokovic's focus immediately returned to tennis on Saturday when he returned to Flushing Meadows for the annual Arthur Ashe kids' day.
After practising on the center court, the Serbian was besieged by autograph hunters then the media as he retreated to the conference room.
Djokovic has played in each of the last three U.S. Open finals, winning the title in 2011, and remains among the favourites this year despite mixed results this season.
He won his third successive Australian Open in January and made the final at Wimbledon, losing to Andy Murray, who also beat him in last year's U.S. Open final.
His build-up to the U.S. Open has been solid without being spectacular as he reached the semi-finals in Montreal then the quarter-finals in Cincinnati.
"I thought I played quite decent in these two weeks," he said.
"Just that both matches that I lost were 7-6 and 7-5 in the third set, and in important moments, I wasn't finding that maybe extra strength to be calm and to play the right shots.
"That's what happens, you know. You go through these periods. But my confidence is still there."
At 26 and with six grand slam titles already under his belt, Djokovic is at the peak of his powers and showing no signs of slowing down or waning interest.
"I feel that I'm in my prime in my tennis career and I really want to keep on playing tennis at this level hopefully for years to come," said Djokovic, who plays Lithuania's Ricardas Berankis in the first round.
"As long as I have the desire, as long as my body holds on, as long as, you know, there is this love, flame of love for this sport inside of me."