American second seed Serena Williams will become the oldest player to hold the WTA Tour's number one ranking on Monday.
Williams, 31, saw off Czech seventh seed Petra Kvitova at the Qatar Open on Friday, to ensure she returned to the top ranking for the first time since 2010.
The second seed and 15-time major winner beat Kvitova 3-6 6-3 7-5 in Doha, to reach the final four of the WTA Premier event where she will meet Maria Sharapova.
Sharapova earlier dismantled Australian eighth seed Sam Stosur, with the third-seeded Russian winning 6-2 6-4.
It was a surprisingly brutal serving performance from Sharapova, as she landed 70 percent of her first serves and finished with 12 aces.
She also won 32 of 42 points behind her first ball.
On the other side of the draw, top seed Victoria Azarenka was too classy for Italian sixth seed Sara Errani.
The two-time major winner completed a 6-2 6-2 win, and the Belarusian will now face Agnieszka Radwanska in the semi-finals after the Pole beat Caroline Wozniacki 6-2 7-5.