What is the trick shot that Roger Federer pulled off to win against Brian Dabul in round one of the US Open games?

Answer 1

When Brian Dabul lobbed the ball to Roger Federer's side of the court, Federer happened to be at the net. He spun around to run toward the baseline, but a few steps before reaching the wall behind the court, and with his back to the net, Federer swatted the ball between his legs. It landed in a corner next to Dabul, who just raised his eyebrows and shrugged. It was the highlight of day one of the tournament at Flushing Meadows. Federer had made a nearly identical through-the-legs-with-his-back-to-the-court shot against Novak Djokovic in the 2009 US Open semifinals.