The Williams sisters discuss tactics during a doubles encounter at SW19

Defending champion Venus Williams insists she will not lack motivation when she meets younger sister Serena in the women's singles final on American Independence Day tomorrow.

The pair duly overcame Russian opposition, in contrasting styles, on another sweltering day at SW19, to set up their fourth Centre Court duel in eight years.

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Their victories over Dinara Safina and Elena Dementieva will ensure the Venus Rosewater Dish will take up residence in the Williams ranch for the eighth time in the last 10 years but Venus insists that will not dull their competitive edge.

"It is different because I'm happy for her to be in the final but I have to face her and defeat her," she said.

"I don't necessarily want her to lose but for sure I want me to win.

"Maybe that doesn't make sense but, when I'm playing someone else, for sure I want them to lose.

"I don't like to ever see her disappointed in any way. But at the same time, I don't want to see myself disappointed. I need to get my titles, too.

"I definitely wanted to play against her because the dream has come true for both of us and for our family."

The pair's progress into tomorrow's final could hardly have been more different, Serena overcoming Dementieva in the longest women's semi-final in Wimbledon history and Venus blitzing Dinara Safina in the second shortest.

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Serena dropped her first set of the Championships and saved a match point before squeezing through 6-7 (4-7) 7-5 8-6 in an epic duel against an inspired Dementieva that lasted 11 minutes short of three hours.

The only previous semi-final to have stretched past two-and-a-half hours was the 1994 battle between Conchita Martinez and Lori McNeil, which lasted 14 minutes shorter.

"I guess I'm always trying to do something to make history, so here I go again," said Serena.

Venus, on the other hand, took just 51 minutes to beat Russian number one Safina 6-1 6-0 and make a nonsense of the world rankings, and she was promptly made 8-11 favourite to complete a title hat-trick.

Venus is determined not to lose her focus and, with previous meetings level at 10-10, insists there will be no sentiment when it comes to family affairs.

"It's real easy to separate it when you get a serve at about 127mph and it comes back as a winner," she added.

"You soon realise you're playing against an awesome player and you'd better really get ready on your toes.

"I'm still the big sister but I'm going to play great tennis."

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