By peoplestaff225
Updated September 08, 2009 02:00 PM

Roger Federer may be the world’s top tennis champion, but when it comes to changing diapers as a first-time dad, he says he is still capable of a double fault.

“Thank God nobody is judging me on it,” Roger told PEOPLE at a press conference Monday following his victory over Spain’s Tommy Robredo at the U.S. Open in New York. “It’s hard! But I’m still trying to be good at it.”

The Swiss pro, 28, and his wife Mirka Vavrinec Federer welcomed identical twin girls Charlene Riva and Myla Rose on July 23rd in Switzerland.

Off the court, the tennis ace takes his daddy duties in stride and tries to enjoy every moment with his babies.

“It’s been a lot of fun being a father and spending time with them,” he said of his 6-week-old twins. “I’m hands on as much as I can because everyday is something new and something different. I don’t want to miss anything.”

The 15-time Grand Slam champ says “Father” is definitely his greatest title.

“It’s an amazing feeling to be called a dad,” he said. “I take a lot of pride in that title.”

— Paul Chi