In tennis, hands and fingers are important, but highly visible wrists also are strategic, which is why many of the world's top-ranked players have alliances with such watchmakers as Rolex, Tag Heuer, Seiko, Rado and Citizen. With the first tennis Grand Slam event of the year, the Australian Open, now underway and airing across the U.S. (on ESPN) and internationally, how important are Rafael Nadal, Novak Djokovic, Maria Sharapova, Andy Murray, Roger Federer and others to the category? And who wears what?