Madrid  - Dinara Safina made tennis history for herself and her family when she officially climbed to the world number one position in the women's rankings on Monday.

Safina, 22, is at the top for the first time. Her brother Marat Safin led the men's rankings for nine weeks in 2000, making them the first brother-sister act to be number one in the singles rankings.

"I didn't know about that until recently. I was told that we are the first family. That is a huge honour, and I am proud of my brother, he has achieved everything in tennis," Safina told German Press Agency dpa in a telephone interview.

Safin is playing in the dusk of his career far from the top of the rankings at age 29, but Safina rejects all criticism that he could have done better over the years than the 2000 US Open and 2005 Australian Open title.

"You can think a lot but he could have also won no Grand Slam. I think he has achieved a lot," said Safina, adding: "My brother was always my idol."

Successful brothers and sisters are rare in sport.

Zimbabwe's Cara and Byron Black got to the tennis doubles rankings top, there are the skiing acts of Hanni and Andreas Wenzel of Liechtenstein and Janica and Ivica Kostelic of Croatia, and US athletics greats Jackie Joyner-Kersee and AL Joyner both won Olympic gold medals.

Safina's career has seen a remarkable turnaround in the past year.

Ranked just inside the top 20, Safina was on the verge of quitting the sport after poor results in early 2008, but then got her act together with four 2008 titles and her first big finals at the French Open and the Olympics.

She also made the January 2009 decider of the Australian Open, losing a showdown for the trophy and the world number one position to American Serena Williams.

Safina attributes the rise to coach Zeljko Krajan, who, she said, made her see tennis in a "positive" way.

It has not gone unnoticed that Safina - like Serb Jelena Jankovic last year - is now top without having won a Grand Slam, but she swiftly dismissed any criticism.

"I can win every one of the remaining three Grand Slams of the year. Every one!" she told dpa.

Safina is the 19th number one overall since the rankings were introduced in 1975 as the race for the top has become very tight in recent months with several changes.

"There are many girls in the top 10 who play well. In the past there were only a few, the others were only average," said Safina.

Safina is the second Russian atop the rankings, but considers herself far away from the glamour of the other top-ranked star, Maria Sharapova.

"We are totally different, you can't compare us at all," she told dpa, but added: "We are both fighters, we don't like losing."

After all, for Safina only the on-court performance counts, not the latest designer dress.

"I have no favourite brand and no favourite designer. I simply wear clothes that suit me. I just want to feel good," she said.

That is definitely the case on court and the top ranking adds to the good feeling of the hard-hitting baseliner.

"I am only interested in tennis at the moment, I want to concentrate entirely on that.

"When you realize a dream (of being number one) it is unbelievable and difficult to explain. I want to be the best in everything I do," she said. (dpa)