!Rf The second in a series on the new tennis season's most intriguing stories.

Is there a compelling storyline involving Roger Federer coming into 2010? At one level the question is a joke. For the majority of people who follow sports at all, Federer is the only story in tennis; from a distance, everything and everyone else seems so mortal by comparison. But for those of us familiar with the history of the game and Federer’s place in it, 2009 was the year in which he crossed all finish lines, removed all obstacles, wrapped up all stories, and reached the dramatic emotional peak of his career. With a men’s-record 15 majors and a career Grand Slam, Federer could have walked offstage and called his life’s work complete.

So what does an athlete do when his after-life begins at age 28, when he’s still No. 1 in the world, when he’s just come off a season in which he was two sets from becoming the first man to win the calendar-year Slam in 40 years? I think we’ve found our storyline. Federer may be the first athlete in any sport to show us how a living legend—the best his game has produced—finds the motivation to compete over the course of a significant amount of time.

How will he do? In November, talking to London’s Sunday Times, Federer laughed when he contemplated one of the possibilities. “It feels like the second part of my career right now, although I try to avoid saying that because the second part sounds like ‘neehhhhrrrrrrr’ [motions straight down].” Federer knows that’s an unlikely possibility, of course; he wouldn’t have joked about it if he actually thought it might happen. In the next line from the same interview, he says that he believes he can compete at the highest levels until he’s at least 32 or 33. It won’t be his talent or fitness that allows him to do that—though an injury, something he hasn't experienced to any major, career-changing degree, could alter all plans (Federer has been so healthy for so long, it’s hard to believe he’ll ever be sidelined for any reason.) What will keep him going, what will keep him motivated even after he’s broken all records, is a simpler but much more reliable force: his vaunted love of competing at tennis.

Another guy who spent a lot of time competing as a living legend, Michael Jordan, never stopped needing to prove himself, to his opponents and to the fans who may not have seen him play before. Federer is not as vicious or personal a competitor as Jordan; he’s driven less by the desire to conquer and more by the satisfaction he gets from living up to all of his athletic gifts and putting on a superior tennis performance.

We know that already. We also know that pretty much anyone would love competing at tennis if he won as often as Roger Federer wins. (I love to compete, therefore I do it well, which makes me love to compete even more, which makes me do it even better—it's a beautiful thing he's got going.) What we don’t know is whether Federer will continue to relish the battle as much if he’s losing more frequently, if he’s not routinely putting on the superior tennis performance. In his later years, Andre Agassi seemed to detest everything that came along with the sport—ball kids included—except for the moment of victory (of course now we know that Andre kind of specialized in detesting tennis). In Federer’s case, as in all cases, the years are going to be accompanied by more losses to more players, maybe guys he once owned. We got a glimpse of that possible future today in Doha when Federer lost for the second straight time to Nikolay Davydenko, an opponent he had beaten all 12 times they had played before last November.

When we say a player “loses a step,” it’s usually a figure of speech meaning, more generally, that he just isn’t a good as he used to be. Looking at two of the top-ranked players who preceded Federer, Pete Sampras and Lleyton Hewitt, I’d say it’s consistency, or the loss of consistency, that’s the primary culprit for decline from No. 1. It’s hard to believe now, but in his prime Sampras could rally with someone like Agassi, and his topspin backhand was a heavy weapon. Neither was the case later. As for Hewitt, his game was predicated on the simple fact that he could hit more balls in the court than his opponent. Any drop in consistency, however slight, was going to have a big effect on his effectiveness.

Federer’s game has never been based on consistency. He’s always taken risks by hitting the ball on the rise and lived with the shanks and frame shots that come with that style. But timing those balls, creating those famous angles, and playing a first-strike game is never going to get easier for him. Federer failed to win the calendar-year Slam in 2009 in part because he was outplayed by Nadal and Juan Martin del Potro in the finals of the Australian and U.S. Opens. But those matches ended with similar breakdowns from Federer: In both fifth sets, he couldn’t find the court with his ground strokes, and he lost each of them badly, 6-2. Sometimes it’s his forehand that abandons him; today against Davydenko it was his backhand that he sent sailing into the alleys.

What I found peculiar at the end of last season, and which seemed to be continuing in his quarterfinal match against Ernests Gulbis in Doha, was the relative lack of juice on Federer’s shots. Maybe it’s tied to foot speed, I don’t know, but he suffered from it in losses to Djokovic in Basel and to Julien Benneteau in Paris. Gulbis also dictated long stretches of their three-setter before imploding at the end. Of course, Gulbis hits a monstrous ball and he's going to dictate most matches, but he’s not going to be the last of the big hitters, either. Tsonga, Monfils, del Potro, Soderling: Federer will have to go toe to toe with all of these young bombers in 2010 and beyond.

As I look at the coming season, I’m curious to see how some of Federer's individual match-ups play out: With Nadal, of course, with Murray, who he seems to have turned the tables on, with Davydenko, with Djokovic, with Soderling, and most of all with del Potro. After the Open, Federer wanted badly to beat the Argentine at the World Tour Finals, but he couldn’t do it. He’ll want to beat him even more badly should they face each other in Melbourne. Federer may not win too many smaller events, he may suffer a few bizarre upsets, but that should only make him savor the chance to prove himself against a guy like del Potro on the big stage at a Slam that much more. In 2010, we’ll begin to see if Federer's veteran’s knowledge and savvy can blunt the raw power of brutal youth. Trying to do that has already inspired him to use the drop shot more; we’ll see if he can expand his repertoire again.

I think Federer will win one major in 2010—it could be any of them, though the most likely candidate is Wimbledon, where, like the aging Sampras, his serve and reputation alone can continue to spell the difference between victory and defeat. But is waiting to see if he breaks his own Slam record a real storyline? In my last post, I said that Nadal will be worth watching in 2010 for the emotional roller-coaster he puts tennis fans on from one match to the next. The reason to watch Federer is simpler. It’s the same reason you might have wished you’d seen Muhammad Ali or Pele or Jordan—or, in my case, Lew Hoad and Rod Laver—in their primes. Because, as all those people who don’t follow the sport closely know just as well as you and I, he’s Roger Federer. Because future tennis fans will be jealous that you got the chance. Because you always wanted to know what tennis in the afterlife looked like.