And once again, Roger Federer is out prematurely at a Grand Slam. Federer was upset in the 4th round at the U.S. Open tonight to Tommy Robredo, 7-6, 6-3, 6-4.

It was really sad to watch. The mystique of Roger Federer is vanishing as each crushing Grand Slam loss mounts one over the next. On break points tonight, Federer was an astoundingly poor 2 of 16. On some of those break point chances, he was bad as he's ever looked—backhands hit listlessly into the net, forehands ugly and wide. "I missed so many opportunities," Federer said after the match.

Thanks to a hours-long rain delay this afternoon, the Federer-Robredo match was sent over to Louis Armstrong, the U.S. Open's no. 2 court. It was the first time Federer had to play there in seven years. The stadium had to be part of the problem. Federer looked as uneasy as Anna Wintour, who was watching Federer from a super-cramped seat in the lower rows at Armstrong. And then there was the specter of Rafael Nadal. The two have played in 10 Grand Slam matches, but never in New York. They were all set up to play in the quarterfinals on Wednesday. It would finally happen: only Tommy Robredo and Philipp Kohlschreiber stood in the way (no Andy Murray or Novak Djokovic to dash these dreams). In fact, Federer was asked about it a couple of days ago. How have they never played here?

"Maybe more his fault," Federer said.

Meanwhile, there's Nadal's name being announced at Arthur Ashe Stadium as he was making his way onto center court, loud enough to echo throughout Louis Armstrong Stadium. Nadal's name was shouted a few moments after Federer went down a break in the second set—a set that he'd lose shortly thereafter.

The loss will only accelerate talk of Federer's retirement. He lost in the second round at Wimbledon and this is the first time in 11 years that Federer has not made a Grand Slam final. Grand Slam champions Venus Williams and Lleyton Hewitt have played quietly into their 30s; it's OK if they get bounced early from a major (Williams has lost in the second round at the U.S. Open for three consecutive years). But with Federer, 32, it's all different.

"I mean, I struggled throughout, which is not very satisfying, to be honest," Federer said after the match. "I mean, Tommy did a good job to keep the ball in play and make it difficult for me today. I missed so many opportunities. Rhythm was off."

But Federer, who has said he wants to play through the 2016 Olympics, sounds like a guy who's looking to play more, even if it means his ranking—currently 7th—continues to nosedive.

"I've definitely got to back to work and come back stronger, you know, get rid of this loss now as quick as I can, forget about it, because that's not how I want to play from here on," he said. "I want to play better. I know I can. I showed it the last few weeks, that there is that level. So, today was pretty frustrating."

But even Federer conceded this: He's just not that consistent anymore.

"Maybe—how do you say—my consistency is just not quite there yet," he said. "Maybe on a daily basis, set-by-set or point-by-point basis, maybe that's something that has been difficult for me, you know."