LONDON -- Think great men's rivalries in the Open era and what comes to mind? Probably these to start: Pete Sampras-Andre Agassi, Roger Federer-Rafael Nadal, Ivan Lendl-John McEnroe, Boris Becker-Stefan Edberg and McEnroe-Jimmy Connors.
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Rafa versus Novak Djokovic should be on the list somewhere. The two met for the 23rd time in London, an encounter Nadal won 7-5, 6-2 at the World Tour Finals. Most of the drama, in the end, came courtesy of Djokovic's right eye.
Given their ages -- Nadal is 24 and Djokovic 23 -- they're on pace to surpass the 36 matches shared by the ice-cool Lendl and temperamental McEnroe, even if Wednesday's affair was only their second of 2010.
Here are three reasons why we should savor the rivalry.
The punishing rallies
Nadal and Djokovic are two of the best athletes on the tour, and they're the two best movers. It often means matches where 20-plus-stroke rallies are common.
The second point of the sixth game at the O2 Arena was a beauty. Nadal and Djokovic took turns windshield wiping on the baseline, both stretched, with the latter finally forcing an error. With great court coverage, clean winners are hard to come by.
In soccer, a stat that often pops up is distance covered by a player. Get the tracker out for these two.
Of course, long exchanges translate into prolonged, exciting matches. They memorably grinded for more than four hours on clay -- in a three-setter -- last year in Madrid, and this September's U.S. Open final wasn't so bad, either.
There's more to come from Djokovic on clay
Before Robin Soderling came along, the man most likely to dethrone Rafa on clay was Djokovic. Next year, and perhaps in the years to come, he'll be a threat for the Mallorcan at the French Open.
Had Djokovic taken any of his three match points against Nadal in Madrid, the Serb might have won at Roland Garros weeks later. As it turned out, the epic clash KO'd them both.
Unlike the overwhelming majority of pros, Djokovic believes he can overcome Nadal on clay, which is a big part of the battle.
Expect them to battle in more Grand Slam finals in general, since Djokovic appears to be on the rise -- again.
You get your money's worth
And we're not simply talking about the rallies.
Rafa's shorts tugging, Djokovic's incessant ball-bouncing, and the Spaniard's lingering between points may annoy a few, but the acts stretch proceedings.
Wednesday, Djokovic was forced into a bathroom break late in the first set to change a contact lens. It became an issue the entire evening, with Nadal visibly riled and complaining to a tournament supervisor. He softened his tone postmatch.
Their quickest match, incidentally, lasted 77 minutes -- one minute longer than Wednesday's first set between Nadal and Djokovic -- and that was on an indoor hard court. As a fan, would you prefer a 50-minute job?
It all adds to the drama. Few, including Federer, complained about Nadal's antics in the aftermath of the historic 2008 Wimbledon final.