By Martin Rogers, Yahoo! Sports 9 hours, 50 minutes ago

Have you heard the one about the Swiss, the Spaniard, the Scotsman and the Serbian?

Apart from being a nightmare for anyone cursed with a lisp, the above sentence represents the elite of men’s tennis. And the joke is on the United States.

The power base of the men’s game is no longer stationed in North America, with the dwindling U.S. talent stocks rarely more apparent than right now.

Andy Roddick sits at No. 5 in the rankings and remains a consistent contender despite only having one Grand Slam title to his name. However, the epicenter of the sport has shifted to Europe, with Roger Federer, Rafael Nadal, Andy Murray and Novak Djokovic having sat tight in the leading four spots...