'And there’s that familiar little second of shocked silence from the New York crowd before it erupts, and John McEnroe with his color man’s headset on TV says (mostly to himself, it sounds like), "How do you hit a winner from that position?" And he’s right: given Agassi’s position and world-class quickness, Federer had to send that ball down a two-inch pipe of space in order to pass him, which he did, moving backwards, with no setup time and none of his weight behind the shot. It was impossible. It was like something out of "The Matrix." I don’t know what-all sounds were involved, but my spouse says she hurried in and there was popcorn all over the couch and I was down on one knee and my eyeballs looked like novelty-shop eyeballs.
Anyway, that’s one example of a Federer Moment, and that was merely on TV — and the truth is that TV tennis is to live tennis pretty much as video porn is to the felt reality of human love.'
As best I can tell, this is the actual shot described in the excerpt you quoted. It's great but perhaps DFW embellished a bit in the retelling: https://www.youtube.com/watch?v=jDwG5rJVtdc
One writer reconsiders the piece: https://theoutline.com/post/7424/david-foster-wallace-roger-...
[1] https://www.esquire.com/sports/a5151/the-string-theory-david...