It may not be too soon to panic.
Four Americans secured spots in the year-end top 10 — Venus and Serena Williams, Andy Roddick and James Blake — and the sizzling sisters have won the last three Slam titles, so there’s little reason for U.S. fans to mope and moan when thinking about what is to come for the rest of ’09.
But by the time the new decade rolls around, there may be good reason to panic. In ’08, America ended the year in a curious position — with only eight men and five women in the top 100. More significantly, only two top-50 players — 21-year-old Sam Querrey and 24-year-old Bethanie Mattek — are under …