Nadal standing in way of history for Federer

With seven Grand Slam titles, Roger Federer is halfway to Pete Sampras' Open era record of 14. Further, if Federer wins the French Open, not only will he own all four Grand Slam titles at the same time, but he will have a legitimate shot at joining Rod Laver as the only players in the Open era to win all four Grand Slam titles in the same season. (Federer won the Australian Open and is the defending champ at Wimbledon and the U.S. Open.) This is probably the story line of the French Open.

However, like Sampras, the only Grand Slam Federer has yet to win is the French Open.

And the one player standing in his way is Rafael Nadal. The French Open defending champ. Owner of a 53-match win streak on clay. And the only player to beat Federer in 2006, going 3-0 against him.

Federer vs. Nadal is one of the anticipated matchups of the year because Nadal is Federer's obstacle to winning Roland Garros and the calendar Grand Slam. He's chasing history and Nadal is in his way. People want to see Federer and Nadal play anywhere, any time. Each tournament it is going to take five or six wins by each to get them on the same court for the final, so we have to cherish every time they play. It would be a letdown if it's anybody else meeting in the final. First, I don't think Nadal will be challenged by anyone else in the field. There are so few worthy challengers for him that in order to make it a competitive final for Nadal you want to see Federer there. On the other hand, if Nadal is upset before reaching the final and Federer reaches the final, it's still compelling, because he has the obstacle of having to win the French Open.

These two -- with their dominance -- have created a rivalry in the last four months, with three classic matches, all won by Nadal. With the matches, as epic as they have been, I don't know how you can't call it a rivalry. Nadal is clearly Federer's obstacle to winning the French, and Federer is Nadal's obstacle to winning majors off of clay. A lot of people feel if Nadal had played in the Australian Open he could have been the man to beat on that court. If these two stay healthy, we have some years to look forward to watching these two go at each other.

Federer says he feels more comfortable on clay and is learning things every match. He's never been uncomfortable on clay -- it has just been a matter of closing the gap between the top players on that surface. Right now, based on form, you would have to say Federer is the second-best player in the world on clay behind Nadal. That's pretty remarkable when you look at other players who have been No. 1 and dominant on other surfaces. You could never say Pete Sampras was the second-best bet to win a tournament on clay, or John McEnroe or any of the other players who struggled at the French. Federer is the second-best player on clay, clearly. Yes, he can be challenged and there's a short list of players who can beat him in Paris, but he's established himself as the No. 2 player on this surface, which speaks volumes to his talent.

"Federer's obstacle to immortality is this man in this tournament on this surface."

However, the margin for error is so small against Nadal. He's so hard to beat that if you rush one forehand and make an error or spray one ball, then all of a sudden you become a little tentative with a shot into the open court that nobody else can get to but Nadal. He runs it down and forces you to keep playing the point. Federer was so close to winning the match in Rome, but every time he loses to Nadal, it's clearly in his head. And that's what makes this tournament so fascinating because Federer's obstacle to immortality is this man in this tournament on this surface. Nadal is what stands in the way of history for Federer.

Federer is a huge favorite at Wimbledon and a very solid favorite at the U.S. Open, but he's the second choice at the French. Watching a champion respond to the ultimate challenge and watching one man represent an obstacle to another man's pursuit of history is always one of the most interesting things in sports, and is the most interesting thing about this tennis season.

Federer is such a huge favorite when he takes the court against most players throughout the year, but not on this surface against this guy. He's the underdog.

ESPN's Chris Fowler will provide analysis for ESPN.com during the French Open.