Whether it was bona fide animus or staged theater for the benefit of television, much has been made of the apparent - or should I say overt - tension on display between longtime rivals Pete Sampras and Andre Agassi during the Hit For Haiti charity event held Friday night in Indian Wells, California. For those of you who haven't seen or heard about it, you can see the highlights here.

The banter of the two Americans overshadowed what was to have been a lighthearted and benevolent affair. Although in actuality more people are now aware of the match and its charitable aim because of the controversy so it'd be wrong to characterize their behavior as robbing the event of its mission.

And one shouldn't have been all that surprised by their tense interactions, especially with Agassi. The Las Vegas native's penchant for emitting confusing competitive and emotional signals has always been a trademark of his personality as fully evidenced by the fallout from his compelling autobiography released late last year. And unfortunately he used his book as a platform to toss a few not-so-benign and unneeded insults at Sampras, in between the fascinating insights into himself and the sport that he offered up.

Of course the other two participants in that doubles exhibition in the California desert, Roger Federer and Rafael Nadal, are also in the midst of a stirring rivalry. And in fact, if one examines their respective rivalries on match play alone, the play of Federer and Nadal has been far more sustained and exciting than when Agassi and Sampras went at each other on tour. Simply put, Federer and Nadal's rivalry is better.

Obviously, both of these rivalries contain the necessary ingredients and contrasts that are so important in sports. As has been enumerated countless times Sampras was the quiet, serve-and-volleyer (though he was an all-court player as well) whose serve is rightfully regarded as perhaps the finest stroke in the history of the sport; Agassi was the extrovert and reluctant tennis champion who relied on his powerful groundstrokes and eerily precise returns of serve. So in both personal style and method of play, they were the perfect foils.

Federer and Nadal also supply the requisite characteristics that make up riveting competition. Federer is perhaps the ultimate champion in manner and style as he glides through the court in a "quiet assassin" manner and can deliver shots from every position on the court; Nadal is the swashbuckling southpaw whose combination of foot speed and vicious topspin has singularly befuddled the great Federer and his superior head-to-head record against Roger is the only asterisk on Fed's otherwise peerless tennis resume.

The one component of Sampras vs. Agassi that Federer vs. Nadal will never possess is that of longevity. With Federer almost 30 and Nadal's increasingly fragile knees, we'd be lucky to enjoy two more stellar years from this duo. And this is where the "which battle is better" question has some merit because Sampras and Agassi started competing from the age of 10 and their professionally rivalry dated a full 13 years. Consider that Sampras' first and last Grand Slam triumphs - the 1990 and 2002 US Opens - came against Agassi.

But during that 13 year span and over their 34 matches (Sampras won 20 of their meetings, 60%) this terrific tandem contested Grand Slam finals on only five occasions - they played each other a total of 10 times in the Slams. And no matter how prolific a rivalry is in tennis, it is Grand Slam matches that count the most in the Open Era. And in those Slams, Sampras dominated Agassi, winning four of their five finals (for his part, Agassi got the better of Pete - barely - in their Slam appearances that weren't the finals, winning three of five quarterfinal and semifinal contests).

To be fair, Agassi and Sampras would probably have faced off in additional Slam finals had they not competed in a stronger era with a much deeper field of champions than there is today. They had to deal with not only each other but also Ivan Lendl (early on), Boris Becker, Stefan Edberg and Pat Rafter to name a few. Until Novak Djokovic, Andy Murray or Juan Martin Del Potro prove they can sustain a high level of play over several Slams, men's tennis is still the Roger and Rafa show. Additionally, Agassi went AWOL a couple of times in the 90's - specifically late '92 through early '94 and again from late '96 until early '99 - while Sampras continued to rake in his Slam trophies. "What ifs" always abound in any comparison conversation and these are valid points.

But already in a span of just five years, Nadal and Federer have met each other eight times in the Slams, with an astounding seven of them coming in finals. Nadal owns their Slam rivalry having defeated Federer in five of seven such matches; three years in a row, 2006-2008 on the Parisian clay, their epic duel in the 2008 Wimbledon final and a near-epic battle in the 2009 Australian final. For his part, Federer defeated Nadal in the 2006 and 2007 Wimbledon finals. This compressed intensity of their rivalry is simply unprecedented in the Open Era (1968 onwards). The duo have gifted tennis fans by playing at their peak level concurrently which is a rarity. Consider that other "greatest rivalry" between messrs. Borg and McEnroe really only lasted 18 months.

Also, these rivalries' respective Slam records is where it gets interesting. The more questions and angles one can generate in such comparisons, the more fertile ground it is for debate and a larger, richer narrative emerges.

The fact Sampras owns such a dominating record against Agassi in those Slam finals is hardly surprising. Sampras was the better player - except on clay - and there is little dispute about that. It was indeed the case that if Sampras was serving at his best, Agassi had little hope in the end of beating him. Form held true.

With Nadal and Federer it's an entirely different matter. Nearly all observers of the sport would state unequivocally that Roger is a better player than Rafa. But if one is of such belief, than a reconciling of the numbers is in order - and not just the excuse that Nadal is the exception that proves the rule. These ceaseless and fascinating questions - hopefully to be revisited in Paris in May - is what makes the Federer vs. Nadal rivalry the best of the modern era in addition to being one of the truly special happenings in sports over the last 40 years.