Roger Federer narrowly escaped upsets a few times at this year's U.S. Open, notably needing five sets against two unseeded players in the first and second round. On Wednesday night, Federer's luck finally caught up with him -- the five-time U.S. Open champion lost to Juan Martin del Potro in the quarterfinal.

Del Potro received major support from the New York crowd at the site of his only Grand Slam title. The Argentinian took a close first set 7-5 before Federer responded with 6-3 second set win. But del Potro stepped on the gas in the third set and didn't let up, winning the last two 7-6, 6-4.

There's no doubt del Potro has fans excited about adding another U.S. Open title to the one he won way back in 2009. Although the victory over Federer wasn't as exciting as the comeback win against Dominic Thiem earlier this week (in which he fell ill, but still managed to climb back from two sets down), it's sure to put more tennis fans on notice of del Potro's renaissance as he approaches a semifinal showdown with Rafael Nadal on Friday.

"I think it's my home court, too," del Potro said in an on-court interview when asked about beating Federer at a venue the Swiss legend has dominated in the past. Del Potro paused as the crowd cheered then addressed the folks at Arthur Ashe Stadium directly: "You make me feel happy every time I play here."

While the reemergence of del Potro is a terrific story, his performance did nix the Federer-Nadal semifinal fans were eying all tournament. Amazingly, Federer and Nadal have never faced one another at the U.S. Open. As both march on toward the tail end of their careers, the chances of the world's two most famous men's tennis players squaring off in New York become less and less likely.

"It's hard to explain, I didn't play that badly," Federer said. "I just ran into a guy who was better on the bigger points. I don't deserve to still be in the tournament."

Cy Brown writes about football, golf, soccer and other stuff for Sports on Earth. Follow him on Twitter @CEPBrown.