LOS ANGELES (AFP) - Serbian tennis star Jelena Jankovic is to replace compatriot Ana Ivanovic at the top of the world rankings, the WTA said on Saturday.

Jankovic, who crashed out of the quarter-final of the US Open to an unseeded player on Friday, will become the 18th world number one since 1975, the association said.

"Since I was a young girl, it has been my dream to become number one in the world," Jankovic told the WTA website. "When you get older, at least one day you can say you were number one and no one can take that away from you."

The 23-year-old has been in scintillating form over the year, winning in Rome and reaching finals at Toronto (2007), Beijing (2007) and Miami (2008) and six semi-finals, including two out of three Grand Slams (Australian Open, Roland Garros).

Jankovic now joins an exclusive club which boasts members such as Chris Evert, Martina Navratilova, the Williams sisters, Martina Hingis and Lindsay Davenport.

WTA will publish the rankings on August 11.