NEW YORK: Serena Williams has officially secured the 2015 WTA Year-End World No.1 Singles Ranking, presented by Dubai Duty Free, for the fifth time in her illustrious career.

Williams, who also finished at No.1 in 2002, 2009, 2013 and 2014, is just the fourth player since the inception of computer rankings in 1975 to finish the year as the top player in five or more seasons, joining Steffi Graf (eight times), Martina Navratilova (seven times) and Chris Evert (five times).

The American is currently spending her 257th career week as the No.1 player in the world.

"Our congratulations to Serena who is a worthy winner of the WTA Year-End World No.1 Singles Ranking, presented by Dubai Duty Free," Colm McLoughlin, Executive Vice President, Dubai Duty Free, said of the 21-time Grand Slam champion. "We wish her well for the remainder of the season and look forward to seeing her play in Dubai in the near future, where she has many ardent fans."

"This year Serena has been truly remarkable. Earning the WTA Year-End World No.1 Singles Ranking, presented by Dubai Duty Free this early in the season is a testament to what a great athlete and competitor she is," said Stacey Allaster, the Chairman & CEO of the WTA. "By winning her second Serena Slam and assembling a near-perfect record, Serena has accomplished things very few have ever done before. She continues to inspire fans and young athletes all over the world and it's an honor to continue to witness history in the making from such an outstanding, deserving athlete and leader."