Without a doubt when Todd Martin came back from 2 sets down against Carlos Moya at the 2000 US Open. He saved a match point and 17 of 18 break points. At one point in the arly morning he called everyone that was left in the stands down to the bottom. When he finally finished at 1:22 AM he smashed his racquet and ran around giving hi 5's to the excited crowd. I talked to someone who was there and he said he's never seen a crowd so involved with a match. Here is a news article and some pics.
"Giddy and delirious, exhausted but never more alive, Martin hurled his racquet to the court, leaving it a twisted, mangled mess as he beamed at his box. Fueled by the adrenaline of the few hundred fans who had cheered him to victory, Martin pushed his tired legs just a little more, lapping the court and giving high fives to people as they hung over the edge of the walls.
"That was me wanting them to know how happy I was, and also me wanting them to know how pleased I was that they could be a part of it," Martin said. "It might be out of my public character, but ...for me, there's a lot more than just the guy who people think is the gentleman and nice guy on the tour."
During his drive to the final at last year's U.S. Open, Martin rallied from two sets down against Greg Rusedski in another fourth-round, late-night match, buoyed by a partisan Arthur Ashe crowd that needled Rusedski and cheered Martin's every winner. Martin has won seven career matches after dropping the first two sets, four of them at the U.S. Open.
"I don't feel like it's necessarily deserved to be able to live out dreams like last night two times," Martin said. "The most important thing is that you seize the moment when you have it, and fortunately, it's happened a couple of times now."