SAP Open 2013: John Isner's Loss Is Bad Sign for Future of American Tennis

John Isner is considered to be the best American tennis player, but his loss in the SAP Open semifinal is a bad sign for the future of U.S. tennis.

Isner's exit was at the hands of Tommy Haas, who hadn't reached the final of any tourney in six months. The veteran was in no way a favorite to win this match, but that didn't stop him from defeating Isner in straight sets.

The biggest problem for the 27-year-old was a 58 percent success rate on his serves.

This was Isner's third event of the year. He didn't compete in the Australian Open as a result of a bruised knee. 

Early exits are quickly becoming a common theme for Isner's showing in most tournaments.

In January, Isner was bounced from the ATP Apia International Sydney when he lost in the second round to fellow American Ryan Harrison. After that, he suffered another disappointing loss in the Davis Cup World Group Round 1 against Brazilian Thomaz Bellucci.

Isner has won just five singles titles in his career. After winning a career-high two in 2011, Isner was unable to improve on his total, and instead, matched it in 2012.

Upon Andy Roddick's retirement last year, Isner took over as the premiere tennis player on the American scene. Because Roddick only won a single major during his career, Isner doesn't have enormous shoes to fill.

The hope for Isner topping Roddick's career total of one Grand Slam tourney win and putting American tennis back on the map isn't looking so good. Isner has routinely failed to make a serious impact in majors with his best showing coming during the 2011 U.S. Open when he made it to the quarterfinals.

As for singles titles, Roddick compiled 32, so clearly Isner has a lot of work to do if he hopes to surpass his predecessor one day.

At the age of 27, the time for Isner to rise to the top is now. He doesn't have too much time before his prime years are gone, so Isner must begin making his way to the head of the sport as soon as possible.

But with his track record at major events and his recent ousting in a tournament full of lesser players, the future is not bright for Isner and American tennis.