Sydney, Australia -- (Sports Network) - Former champion Lleyton Hewitt will skip the U.S. Open after undergoing hip surgery.

The former world No. 1 and two-time Grand Slam titlist was the 2001 U.S. Open champ and runner-up in 2004.

"Surgery was always the last resort, but unfortunately that's what it came down to," Hewitt said. "I am also shattered that I can't lead the Australian Davis Cup team in Chile in our bid to rejoin the World Group, and hope that the boys can still come through with a great win."

The Aussies will face the host Chileans in a Davis Cup World Group playoff in Santiago in September.

The 27-year-old Hewitt lost to new world No. 1 Rafael Nadal in the second round at last week's tennis tournament at the Beijing Olympic Games. The fiery Aussie is 20-11 this season and currently ranked 55th in the world after opening the year at No. 21.

The 2008 U.S. Open will get underway Monday at the USTA Billie Jean King National Tennis Center in New York.