London: Former world number one Roger Federer believes the current dearth of top class American players is bad for the game.
For the first time since the rankings were introduced no American is among the world's top ten in the men's or women's lists.
Federer, however, believes the United States is merely suffering from a general lack of emerging talent which can also be seen elsewhere.
"There are not that many teenagers in the top 100 so I think many countries are going through a phase where they do not have the talent they hoped to have," said the Swiss, who is currently ranked third in the world.
"Even in France, Germany, England or America, all those countries are struggling and waiting for an up and coming player like we always hope for like Rafa (Nadal), Novak (Djokovic) and myself, or (Andy) Roddick or (Michael) Chang.
"This is kind of missing at the moment and those countries have to be patient and this creates a lot of pressure on the people working in the federations and the media, especially in the bigger countries like America.
"It's going to be interesting to see how they get through it and I hope they are able to come along with some more big players -- especially for the States.
"I hope they get through it because it's very important for the States to have big players."
He added: "In the women's game I think we are all aware that if they wanted to or if they could play physically then (the Williams sisters) would be in the top 10 without any problems.
"It's worse on the men's side with just a few outsiders but it's a fact that it's the first time in history this has happened.
"It's a bit disappointing for us to not have any Americans in the top players because it is always great to play against American players and have American players in the game but Roddick remains a former number one in the world and a Grand Slam champion."
Federer added he was pleased with the restructuring of the calender this season to make Rome, rather than Madrid, the last clay event before the French Open.
Madrid is played at altitude whereas the conditions in Rome are more similar to those in Paris.
"I think it is better. It is something that we always wanted to have from the beginning and I think we were not quite happy that Madrid was the last slot before Paris," he said.
"I guess it was also something to do with the women's tennis tournaments here in Rome.
"Now it is all ironed out and obviously not having to go from altitude (in Madrid) and going from Rome to the French Open is easier and this is obviously much more similar to Paris than Madrid ever will be.
"I think this way it is just easier for most of the players."