The last time they met was in France back in June, and Robin Soderling stunned the sports world and ended the streak that John McEnroe has--repeatedly--said is more impressive than Joe DiMaggio's 56 game hitting streak: Federer's 23 consecutive semifinal appearance at a Grand Slam.

Soderling won that match at Roland Garros in the quarters in four sets (he'd eventually lose to Rafael Nadal in the Finals).

That has been Federer's only hiccup against Soderling, however. Federer owns a lifetime 12-1 record against the Swede, including a hard-fought win over Soderling in the quarters here last year. Considering that Federer is far more comfortable on the blue courts in Queens than he is on the clay in Paris, it would seem we can comfortably call him a favorite for tonight's best. But the best copy editor in the world and tennis fan extraordinaire, the Observer's Chris Cronis, emailed me last night to say he definitely thinks Soderling is going to win.

Watch out for this one. Upset potential, and it sure would make a bunch of sports writers unhappy.

Federer won in straight sets night, and barely broke a sweat, defeating Jurgen Melzer 6-3, 7-6, 6-3. A-Rod was in attendance! And he may take Roger to his first baseball game.

"Yeah, I met him for three minutes," said Federer. "It's just nice to meet another great athlete. Never been to a baseball game. So that's something on the 'to do' list for me. Surprising enough, he invited me. My schedule is busy, so we'll see if I can make it or not."

Vera Zvonareva also won tonight, and it looks like we're setting up a fantastic second week of tennis. Very few upsets in the first week equals high quality stuff for this week.

Yesterday, Roger got fired with four consecutive questions about Rafa to open up his press conference: Does Rafa's Run at New York compare to your pursuit in Paris? Is Rafa better than you? Are you better because of Rafa? What have you worked into your game because of Rafa?

(When he answered the first question about his hunt for a French Open versus Rafa's hunt for the Open, Federer said, "The only difference so far is that I lost, what? Two finals before? Plus a semis before. Whereas he's never been in a finals here." Yeep! Understood, Roger)

When you compare this opening week to the last few years at the Open, it's night and day. Last year, for instance, even though Nadal made it all the way to the semis, he wasn't asked once about Roger at a presser until after he was eliminated.

The press corps is hungry, and we don't disagree with them. Whatever it takes. Let's get these two in the Finals.

And Mardy Fish is beginning to go on a run like he did in 2008. He won in front of a full-house at Armstrong to advance to the fourth round where he takes on the winner of tonight's Blake and Djokovic match.

Wozniacki and Sharapova absolutely dominated in their matches and that sets up a deliciously exciting Round of 16 match. Wozniacki is the world's no. 1--even though she has never done better in a Grand Slam than being a finalist at last year's U.S. Open--and will take on Sharapova, a former Open champion. We'll be sure to take a close look at the match that may be a de facto Final for Monday afternoon.

Let's ask three former U.S. Open champions--two men, one lady--about love and tennis.

THE SINGLE MAN: MARAT SAFIN, 30

The 2000 U.S. Open champion, who retired last year, did an interview with Russian Hello! in which a revealed a pragmatic, if slightly bleak, view of relationships.

"To have fun together – this is very rare, actually," he said.

Uh oh. Marat said that he hasn't found love because the girls he's dated have been, occasionally, too young. But he's not desperate, either.

"I’m not going to seek a bride from an ad," he said (The guy lives in Moscow! He probably can find that bride outside his apartment). 

If you're lucky enough to get on a date with him, it looks like he's got quite the bachelor pad in Moscow. He makes good use of it! He doesn't like fancy restaurants or any sort of Moscow scene. He likes cooking dinners and spending time at home. But if you do go out to eat with him, watch out, cause he's gonna get judgey!

"Sometimes, you go to the restaurant and see a couple: come, sit opposite each other and sit," he said. "You see that they have nothing at all between them."

THE MARRIED MAN: ROGER FEDERER, 29

Even though Roger recently married (and had babies) with his longtime love, Mirka Federer, he said that it's hard to find love when you're pounding the hard courts.

"We cannot get married that early," he said last night, at a press conference after his victory. "And if we do, you're not going to see the other person maybe for over 50 percent of the year. It's hard to keep up a good relationship, I find."

He wound up doing it, though!

"I was lucky enough that the last seven or eight years, I've been every day together basically with Mirka, and that has definitely helped me to be good," he said.

He acknowledged that when players get married (hello McEnroe, Borg, Agassi!) they "start to maybe not play as well."

His setup, however, is ideal.

"It's so well set up," he said. "Mirka takes such great care. I'm there anyway most all the time as well that I can place my practice whenever I want.  I still have enough time with them."

See, Marat, it can work.

THE SINGLE WOMAN: VENUS WILLIAMS, 30

After Venus won last night, she said love can wait.

"I have a commitment problem," she said. "I can't commit."

Kim Clijsters and Lindsay Davenport found love and happiness, and said, "They don't have a problem, but clearly I do."

What's she married to? Tennis, she said.

"I'll grow up one day, but not yet," she said.

FOR COMPLETE OBSERVER U.S. OPEN COVERAGE: http://observer.com/usopen and http://twitter.com/koblin

Here's the shot:

Ana Ivanovic, who was knocked out of the first round herself last year, came back strongly last night winning in straight sets. She told the press last night that she's confident again, but we've heard that refrain before.

In the featured matches, Venus Williams and Roger Federer both cruised to a straight set victories. Venus said her knee held up OK in the match, but we'll see what happens when she's better tested.

Oh, yes, and also: Anna Wintour told ESPN that Roger Federer does reach out to her to ask for fashion advice.

FOR COMPLETE OBSERVER U.S. OPEN COVERAGE: http://observer.com/usopen and http://twitter.com/koblin

Finally, the press corps seems to be mobilizing, and they've declared what they want: A Nadal-Federer final, and they want it now.

Some examples!

The Wall Street Journal lays the groundwork today, and mentions that "this six-year-old odyssey, surprisingly, shockingly and sadly, hasn't made its way to New York."

The Post led this morning its Open supplement with a Rafa story, mentioning that the two Giants of Tennis haven't met up yet (this story is, somehow, not on the web).

The Times led this morning with a story about Rafa and his ambivalence talking about his place in history. What better way to win in New York and beat Roger.

And, ah yes, The Observer wrote last week that Rafa has never dazzled New York the way he has in Paris, Melbourne and London. With a spirited Roger and Rafa final? Done!

Enter Juan Martin del Potro. In a stunning, four-hour-and-six-minute match, del Potro shocked the New York crowd and the tennis world and defeated Federer in five sets, winning the last set in especially remarkable fashion, 6-2. It was the first time that Roger Federer has ever lost a Grand Slam final to a man not named Nadal.

The result is particularly shocking because, ninety minutes into the match, it looked like another supposed heir apparent was going to wilt away under the pressure. With del Potro looking weak and unfocused, Federer easily won the first set and looked like he was cruising towards the second. Federer wasn't playing perfect tennis. Far from it. (His first serve percentage, for one thing, was under 45 percent in both of the first two sets.) But del Potro was plainly nervous and unable to capitalize on his opponent's weaknesses, and Federer advanced to a 5-3 lead in the second set.

That was when we were introduced to the del Potro forehand. Reintroduced, rather; this was the shot that overwhelmed Nadal yesterday. It's hit at more than 100 mph, and its snapping sound reverberates perfectly up to the highest seat at Ashe. Thanks to that forehand, with Federer serving for the second set, del Potro, unbelievably, broke him and then took the set in a tiebreaker.

But it's gut-check time, right? Federer wouldn't roll over. He won the third set comfortably, 6-4. After all, this is what champions do, and it looked like we were going to watch Federer win yet again, even if it was a competitive test. Just another great story for the Federer annals. But then, in the fourth set, with Federer up 5-4, and two points away from the championship, del Potro didn't get nervous, held his serve, and, giving off a Marat Safin vibe from his 2000 U.S. Open men's final upset of Pete Sampras, demolished Federer in the tiebreaker. He got the early break in the fifth and then absolutely bombarded a glum and confused Federer the rest of the way.

Del Potro's forehand and serve were masterful by the end, but his ability to win on the biggest, most pressure-filled points was even more impressive. In the match, Federer had 22 chances to break del Potro's serve, and he was denied 17 of those times. Djokovic let the big moments catch up to him. Same with Andy Murray. Somehow, the 20-year-old Argentine, who we've been hearing about for a year or two as the next breakout star, finally broke out.

He had to do it by beating Nadal in the semis and then Federer in the finals. There's no clearer test.

Now, our next point can easily be cast as a knee-jerk reaction, but we saw tonight a glimpse--small but real--of the twilight of Federer's remarkable dominance over the game.  All credit to del Potro in this match, but Federer, from start to finish, played medicore tennis at best, and poor at worst. His first serve percentage was 50 percent. He missed 17 break point chances. He hit into 11 double faults. He made 56 errors (in the fifth set, on the biggest stage in tennis--the time and place Federer has always shone brightest--he hit into 15 unforced errors versus 4 winners).

If Federer won the Open, it would be called a career year--three Grand Slams on three different surfaces. But really, on reflection, we're beginning to watch Federer get tested in a way we never have before. He lost the Australian Open after being torched by Nadal in the final set. In the French Open he never had to face Nadal, and he had to play two five-set matches that he barely eked out (one to Tommy Haas, and one to, you guessed it, Juan Martin del Potro). At Wimbledon, it took him 30 games in the fifth set to beat Andy Roddick, a guy who has never otherwise come even close to him in a Grand Slam match. But tonight, quite frankly, Federer laid an egg. Del Potro was playing admirably gutsy tennis, but he didn't have the best day of his life, either (he had more errors than winners in this match, and we would go as far to argue that he actually played better in his five-set loss to Federer at the French).

Either way, you can't help but feel there's a changing of the guard in tennis--or, at least, a more crowded stage at the top. Juan Martin del Potro did something that Andy Murray hasn't done and now we hope he capitalizes on it in a way that Novak Djokovic, thus far, has not

Don't let us down, Juan Martin. And hey, you can smile now!

Anna Wintour left tonight's men's singles final between Roger Federer and Juan Martin del Potro during the fourth set, a moment when Federer was leading two sets to one and had the match seemingly in hand. Federer wound up losing that fourth set, and ultimately the match, to del Potro. It was the first time Federer lost at the U.S. Open since 2003.

Earlier today, Vogue's spokesman, Patrick O'Connell, told us that Wintour would be attending Marc Jacobs' spring 2010 show, scheduled to begin at 8 p.m. tonight. Wintour left her seat in Federer's box--where she was seated next to Gavin Rossdale and Gwen Stefani--just before 7 p.m. Mr. O'Connell also said that Wintour would miss the Thakoon show today because of Federer's match. Though she did make it to part of Donna Karan's show earlier this afternoon, Wintour left that show early.

Wintour, as usual, has been spotted in Federer's box throughout the tournament this year, including during Federer's third-round victory over former U.S. Open champ Lleyton Hewitt. "Well, Lleyton is a very tough competitor, and he was getting every serve back," she told us after the match. "But we believed."

Maybe Roger could have used his good luck charm tonight!