The 22-year-old Safina, whose brother Marat was the men's top player in the world in 2000, will replace Williams who has been on top for 11 consecutive weeks and 72 in all.
"It's a great honor to reach the No. 1 ranking and it is a dream that every girl who has ever wanted to play professional tennis shares," Safina said.(Image by Torsten Blackwood/AFP/Getty Images)
"It is even extra special for me since my brother Marat was able to reach the No. 1 ranking and I am happy to share this achievement with him."