as she broke serve to reach 2-1 before breaking again to close the set out at 6-3 after winning the last eight points in a row.
However Venus' errors returned once more again early in set three even as her sister began to limp due to a possibly left knee injury. Serena broke serve to reach 2-0 after Venus netted a backhand following the close of one of the longest points of the match.
Serena broke serve again to reach 4-1 after one of Venus' six doublefaults of the match which would prove to be a major weakness for her tonight.
Venus pulled to 3-4 before some inspired play from Serena and more errors from Venus would seal the match in Serena's favor.
Venus netted a final crosscourt backhand after one hour and 55 minutes of play.
The win evened the Williams sisters' career head to head record at ten wins apiece.
In Saturday's final, Serena takes on the 19 year old, 11th seeded Victoria Azarenka of Belarus, who earlier today defeated the 8th seeded Svetlana Kuznetsova of Russia 6-3, 2-6, 7-5 in the day's first women's semifinal.
Serena could have lost the top ranking should she had lost the semifinal.
“Even though she’s my sister, I’m still here to win,” Venus said. “I can’t give anyone anything. So I’m disappointed that I lost tonight, whether or not she kept the ranking or not.”
In other news, the world number one Rafael Nadal of Spain was upset in the men's quarterfinals by the 6th seeded Juan Martin del Potro of Argentina 6-4, 3-6, 7-6(7-3).