“We’re used to being in this position now, so we pretty much have it down,” Serena said Friday after she and Venus beat top-seeded Cara Black and Liezel Huber 6-1, 6-2 to reach Saturday’s doubles final, where they will face Samantha Stosur and Rennae Stubbs.

But even though Serena beat Venus in the 2002 and ’03 Wimbledon singles finals, she already feels like the underdog against a player trying to win her sixth Venus Rosewater Dish.

“I feel like going into this final I have nothing to lose,” said Serena, who is 27 years old, two years younger than Venus. “I feel like obviously she’s playing the best tennis at this tournament.”

Saturday’s final will pit two players with two of the best serves on tour, and both had them working pretty well in the semifinals. Venus holds the tour record for fastest serve at 129 mph, though she had only five aces against Safina. Serena, however, smacked a tournament-high 20 aces against Dementieva.

“I definitely owe this win to my serve,” Serena said, referring to her victory over the fourth-seeded Russian. “I lost serve a couple times, but when it was key and it was time for me to hold serve, I was able to hold serve.”

Against each other, there are no secrets. The sisters have been coached by their father, Richard, and mother, Oracene Price, since the beginning.

“We both play such a similar game. I mean, we had the same teacher,” Venus said. “But what I can tell you is the same is the respect that we have for each other on and off the court.”

Serena — with 10 major titles, three more than her sister — does feel that Venus has a little something that she would like to emulate.

“Her positive attitude,” Serena said. “I get negative a lot. I think it creates who I am as a person, but it’s good to stay positive and stay calm.”