PERTH, Australia, Dec. 8 (UPI) -- U.S. Open champion Serena Williams says a hamstring injury will keep her out of next month's Hopman Cup, an Australian Open tuneup tournament.
The Hopman event is played in Perth, Australia, in early January, two weeks prior to the open in Melbourne, which begins Jan. 19.
Williams, ranked No. 2 in the world, said she plans to play in the open.
The cup is a mixed-team event.
The 27-year-old Williams and Blake won the Perth event in 2003.