Venus Williams admits she acts as a confidante for sister Serena but insists they will not even think of each other as siblings if they both reach the final at Wimbledon.

The duo prepared for today's singles semi-finals by teaming up to beat Bethanie Mattek and Sania Mirza 6-4, 6-3 in the doubles last night.

Mattek and Mirza were 3-0 up in the second set before the Williams sisters stormed back to win six games on the trot and reach the last four, where they will face Nathalie Dechy of France and Australia's Casey Dellacqua.

As the older sister at 28, Venus said: "I absolutely give advice. That's my job. A huge part of my life, is being a big sister. I love that job, it makes me really proud.

"I'm always happy when I can help out. It's definitely one of the joys of my life."

And Serena, 26, responded: "(Playing each other) hasn't changed that or our relationship. We leave everything on the court. We are sisters again the moment we shake hands."

Although both are favourites to make Saturday's women's singles final an all-Williams affair for the third time at SW19, Serena hinted she is not confident of claiming a third Wimbledon title.

Although she admits she usually gets her way in the family, when asked if this would extend to the singles title she admitted: "I'm gonna hope so, but I doubt it."