Is Cilic the new del Potro?

"They are young and playing well. It's not only because they are tall."

Those were the unmistakably blunt words of Rafael Nadal after his loss in the semifinals last week in Beijing. The Spaniard was assessing the current form of U.S. Open champion Juan Martin del Potro and, more importantly, that of the man who had just given him an unceremonious thrashing, Marin Cilic. Fourteen months after winning Olympic gold on the same court in China, Nadal, 23, could muster just four games against the 21-year-old.

A "generation" isn't what it used to be in tennis. On the ATP Tour these days, it lasts about a year. In 2008, Novak Djokovic and Andy Murray, born seven days apart in 1987, established themselves at the top of the ATP rankings. Will 2010 be the year that Cilic, born five days after del Potro in 1988 and currently ranked No. 13, join his fellow big man in the top five?

It won't be because his effort or attitude is lacking. Cilic's coach, Bob Brett, who helped make Boris Becker famous, praises his charge's intelligence, practice habits and levelheaded demeanor. Those traits produced consistent, if unspectacular results until this year's U.S. Open, when Cilic made his first Grand Slam quarterfinal by defeating Murray in straight sets. And they were on full display again last week in Beijing. Cilic showed up at the site a full eight days before the tournament started, and when play did begin he went about his business with an unruffled calm that could only be described as Borgian. In the final against Novak Djokovic, he didn't betray a hint of frustration even after losing the first set 6-2. While he eventually fell in a second-set tiebreaker, it wasn't because he lost his cool. Cilic doesn't beat himself; when he goes down, it's because what he was trying simply didn't work.

Del Potro and Cilic aren't just the same age, they're the same height: 6-foot-6 -- taller than any previous major champion. The game's classicists might be tempted to ask: Is gigantism good for tennis? They should listen to Nadal. As he said, it isn't just because del Potro and Cilic are tall that they're having success. Although both own strong serves, it's their groundstrokes and returns that are their trademark weapons. Their extra width, rather than their height, is what helps them the most. Watch del Potro range far to his right and still connect with atomic power on a forehand. Then watch Cilic reach for a wide serve and manage to keep both hands on his racquet for more power. Being tall may be the future of tennis, but not for the reasons we always thought.

We've known that Federer and Nadal have put together a rivalry for the ages. Will they also go down as the last of the vintage, 6-foot-2 tennis champions? We'll find out more soon. Del Potro put himself in their stratosphere this year. In 2010, Cilic may just reach as high.