When Pete Sampras, the old "all-time greatest tennis player who ever lived", says that he thinks Roger Federer is the best who's ever played the game, that's a pretty big deal. It's like when Jack Nicklaus said he thought Tiger Woods would win 10 green jackets. Since Pistol Pete is better qualified to decide such things, I'm not going to argue. But allow me to present what we'll call an "alternative opinion".
Federer's greatness is undeniable. The 14 Grand Slam titles speak from themselves. But there's one statistic that hurts Federer's cause: In 20 career matches against his rival Rafael Nadal, Federer is just 7-13. Much like the fact that Sampras never winning a French Open is often held against him, how can Federer be thought of as the best ever when it's not entirely certain that he's the best of his era?
Granted, a majority of those 13 losses have come on the clay courts that Nadal dominates. (Federer is 2-9 against Nadal on that surface.) But that still means that Federer barely breaks even against Nadal on his surfaces (grass and hard court). And in Grand Slam finals not played on clay, the two stars have split their four matches. Currently, Nadal has a three-match win streak over Federer in Grand Slams.
Pete Sampras had a winning record against almost every one of his main rivals. Against Andre Agassi, arguably Pete's biggest rival, he had a 20-14 career mark, including 4-1 in Grand Slam finals. Conversely, Federer wins just 35 percent of the time he takes the court with Nadal. Joe Frazier won 33 percent of his bouts with Muhammad Ali (he was 1-2) and it would be preposterous to say that Frazier was the best boxer ever.
That's an extreme example, of course. Like I said at the top, I'm not arguing against Federer. But it's interesting, no?
You could use circular logic to make a similar case against Sampras too, by the way. He had a 4-6 record against Richard Krajicek, for instance, and nobody is arguing that Krajicek is better than Sampras. But in sports you're measured on how you fare against the best. For Federer, that means that to topple Sampras in the history books, he may first need to topple Nadal on the court.