Johannesburg - Uzbek referee Ravshan Irmatov insists he is not nervous as the clock ticks down to the biggest game of his career.

Irmatov has been selected to officiate the opening match of the Soccer World Cup on Friday between hosts South Africa and Mexico - only the second time that an Asian Football Confederation ref has been picked for such a job.

An international referee for eight seasons, he was Asia's top man in the middle in both 2008 and 2009 and has previously taken charge of games at Under-17 World Cups and was also on duty at the 2008 Club World Cup in Japan.

"We are not refereeing for the first time. That's why we are used to this atmosphere. We go and just do our jobs. Nothing extraordinary," the 32-year-old said on the Asian Football Confederation website.

"These kinds of pressure-packed games are the pinnacle of a referee's career," he added. "Every referee dreams of being at the World Cup. Those that don't have that dream are not professional referees.

"And every referee wishes to officiate at the opening game and final of the World Cup. I didn't expect it, but I accept this with great joy."

Japan's Yuichi Nishimura will make it a double delight for Asian referees by taking charge of the second match between former champions France and Uruguay, also in Group A, in Cape Town.