LONDON: Venus and Serena Williams clash in a fourth all-sister Wimbledon final on Saturday determined to prove that their domination of the event is not a backward step for the sport's future welfare.

Despite 128 players starting out in the first round last week, the two Americans are once again left to contest the final for the second successive year and for the eighth time in a Grand Slam final.

Venus won last year to clinch her fifth Wimbledon title and a seventh major; Serena was the champion in 2002 and 2003 and has captured 10 Grand Slam trophies in all.

Despite the success, Russia's Dinara Safina, still without a major, and who was humiliated 6-1, 6-0 by Venus in the most one-sided Wimbledon semi-final in 40 years on Thursday, remains a contentious world number one.

The sisters, who are level 10-10 in career meetings, are desperate to put the controversy over rankings to one side and put on a competitive Centre Court showpiece.

"I think women's tennis is fantastic. I would never be down on it. I happen to have enormous respect for Dinara," said Venus after her 51-minute demolition of the Russian.

"I'm not the number one seed so I shouldn't be expected to win but I have more experience playing on grass courts."

Venus, bidding to win a hat-trick of Wimbledon singles titles, is more concerned about quelling the competitive instincts of her sister who saved a match point in her three-set semi-final win over Elena Dementieva.

At 2hr 49min, it was the longest women's semi-final in history.

Venus recalled the first time she witnessed Serena's battling qualities when she was still a rookie on the tour back in 1998.

"We were playing in Sydney at White City and she was playing Lindsay Davenport. She was down 1-6, 2-5 and I'll never forget that she came back and won," said Venus.

"It was so intense. I just learned so much from that, her fight. I think that actually had a huge impression on my career, that one incident."

As always the final will be closely scrutinised for its competitive edge.

Twelve months ago, Dementieva, who had been defeated by Venus in the semi-final, appeared to suggest that the winner would be a "family decision" although she quickly corrected herself, claiming her remarks had been misinterpreted.

The sisters are sensitive to such accusations.

They haven't played the Indian Wells tournament since 2001 when fans reacted furiously to Venus's decision to withdraw from the semi-finals with an injury.

Venus won a closely-fought final here in 2008 and the sisters have served up two three-setters since, in Dubai and Miami.

"I'm happy for Serena to be in the final, but I have to face her and defeat her. I don't necessarily want her to lose, but for sure I want me to win," said the defending champion.

"Maybe that doesn't make sense. But when I'm playing someone else, 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."

Serena says the final is another step on their journey to fame and fortune which began in the tough Los Angeles neighbourhood of Compton.

"The more we play, the better it gets. When we play our match on Saturday it's for everything," said the world number two.

"This is what we dreamed of when we were growing up in Compton 20 something years ago. This is what we worked for, and this is what we want."