Serena Williams beat sister at Key Biscayne

KEY BISCAYNE: Serena Williams has retained the No.1 ranking by beating her sister Venus in the semifinals at the Sony Ericsson Open.

Williams defeated older sister Venus 6-4, 3-6, 6-3 Thursday in the 20th match between the two. Each has won 10 times. Serena needed to reach the final to retain the top ranking she has held since Feb. 2. Otherwise, No. 2-ranked Dinara Safina would have supplanted her next week.

Serena''s opponent Saturday will be 19-year-old Victoria Azarenka of Belarus, who beat Svetlana Kuznetsova 6-3, 2-6, 7-5. When Serena closed out her victory, she hopped in delight, raised a fist and shouted, ``Yes!'''' She then met her sister at the net with a handshake and slap on the back.