If the mark of a master is the ability to make the difficult seem a doddle, then with one swish of his tennis racket on Sunday Roger Federer underlined, beyond any doubt, his status as master of the courts.
Not one for hyperbole, even the softly spoken Swiss described this magical shot as the greatest he has hit in his life.
It was a show-stopping stroke - attempted week in, week out on park courts, local clubs and school grounds around the world and one, which will not be forgotten by anyone who witnessed it at Flushing Meadows.
Leading by two sets, 6-5 and 30-0 in the third set of his U.S. Open semi-final, Federer took a gently sliced Novak Djokovic serve into his body on the backhand, chipping it back to within a metre of the baseline.
The Serb flung an inside-out forehand wide and deep into Federer's backhand corner, which the Swiss lunged at and flicked back to around the service line.
Spotting Federer behind the baseline, fourth-ranked Djokovic cut a backhand dropshot over the net to set Federer scampering up court. The Swiss barely got there with a forehand stretched in front of his body and his tennis shoes squeaking on the hardcourt surface.
So far so normal, with Djokovic toying with the top seed at this point, and flicking a backhand volley over Federer's head. As Federer turned and raced to the back of the court, Djokovic casually ambled to the net, his racket hanging limply at waist level.
All the coaching manuals advise a scurrying, retreating player chasing a lob to throw up a high, defensive lob in return, to buy some time and allow for repositioning.
Instead Federer attempted the showboating between-the-legs-pass, the shot, which leaves most would-be exponents in a tumbled, tangled mess behind the baseline and the ball nestled in the net - or outside the confines of the court.
Federer, though, chased down the lob, allowed the ball to drop to knee level with his back to the net and cracked it between his legs cross court and past the bemused Djokovic at the net.
Even for Federer it was a special moment. The Swiss bounced up on the balls of his feet and punched the air in joy. The New York crowd rose to its feet and Djokovic threw his opponent a wry smile.
"I mean that shot he hit," marvelled the Serb later. "How can you explain it?
"It was funny. On these shots, you just say, 'well done, too good.' What can you do?"
The question was clearly rhetorical - against a shot like that, there is little you can do. "That's unbelievable. It was the greatest shot I ever hit in my life," Federer said in a courtside interview as he watched a replay of the point on the giant screen on Arthur Ashe Stadium.
"I was in a difficult position. I had nothing to lose I guess," he added.
