In the 25th meeting between the two, elder sister Venus notched her first win over her 17-time Grand Slam-winning sibling since a three-set victory in Dubai five years ago.

World number one Serena, the top seed and defending champion here, still leads their career head-to-head 14-11.

“Big sister taught little sister a lesson…,” world number one Serena wrote on her Twitter account.

The 25th career meeting between the two lasted just over two hours as Venus hammered six aces and had just two double faults.

Many of the crucial points in the semi-final came off second serves as Venus won 56 percent of her second serves compared to just 36 percent for Serena.

The 34-year-old Venus became the oldest player to reach the final of this event in a quarter of a century as she guns for her 46th career singles title.

This also marked the first time Venus and Serena appeared on the same court together since Serena’s infamous wobble at Wimbledon.

Six weeks ago Serena exited Wimbledon in bizarre fashion. Appearing dizzy and bewildered during a Wimbledon doubles match with her sister, she struggled just to bounce the ball and then double-faulted four times in a row. Serena later blamed her performance on a virus.

Serena, a three-time champion at the event and who was coming off a victory last week in Stanford, fired 19 aces but couldn’t overcome her double faults and poor second serves.

In Sunday’s final, Venus will face either third-seeded Agnieszka Radwanska of Poland or unseeded Russian Ekaterina Makarova