DENVER (Reuters) - Juergen Klinsmann shrugged off criticism of his work as U.S. national team coach on Thursday and said he welcomed debate over the team's performance as a sign of soccer's growth in the country.

Klinsmann came under fire from anonymous critics in an article published by the Sporting News on Tuesday and while he was clearly unhappy at not knowing where the sniping had come from he took a relaxed approach to the issue.

"Obviously, I prefer if people have any problems, that they come to me and talk to me about it," he said ahead of Friday's World Cup qualifier against Costa Rica.

"The so-called anonymous quotes, there is no way to know who said it. Is it a player, is it an agent, whoever? But it doesn't distract us at all."

The criticism emerged after the U.S. lost their opening game in the final CONCACAF qualifying stage 2-1 to Honduras last month but Klinsmann said he was comfortable with opinions.

"It's just part of our environment. Journalists and people can say whatever they feel, whatever they believe, which I think is important," said Klinsmann.

"It's a great sign. All the debates are going on in soccer in this country. It shows that people care. It shows that people really question things. People maybe get worried about we lost one game in Honduras, one out of 10 games in all. But you take that as a positive sign."

Some of the critics have questioned whether the German has tried to move too fast with new ideas and new methods during the qualifying process for Brazil 2014 but Klinsmann said change was a key part of his job.

"It is normal that we have had to move players out of comfort zones, we have to introduce them to different methods because we want to make them better," said Klinsmann.

"If we do things exactly the same way before, we are not improving. It's our job to get these guys to another level, and that is only done by using different methods."

The U.S. face a trip to Mexico on Tuesday and will be very keen to avoid heading into that game without three points on the board, given they have never won a competitive fixture against the Mexicans at the Azteca Stadium.

But Klinsmann said he was not feeling any pressure or job insecurity.

"The opportunity is there now to correct the result in Honduras, get ourselves on the right track and hopefully make everyone happy," he said.

"But on the other hand, I am not here to make everybody happy. In that case I actually have the wrong job. I am here to challenge people, I am here to improve people. By doing that, I might take some people out of their comfort zones. That's what I keep doing because I want to make it better."