Williams sisters to meet in final

The 27-year-old American was forced to produce all her battling qualities to overcome a spirited Dementieva, who produced a brilliant performance but still bowed out at the last-four stage for the second year in a row.

Meanwhile, defending champion Venus had a much easier time of things, defeating world number one Dinara Safina 6-1 6-0 in just 51 minutes.

In the afternoon's first semi-final, Serena saved a match point in the second set before forcing a decider and winning 6-7 (7/4) 7-5 8-6 in an epic duel on Centre Court that lasted 12 minutes short of three hours.

"It was really tough," Williams said. "She's been playing so well and has won a lot of matches against me in the past. I was not on my best game but my family were so positive. Elena played so well and we gave the crowd a wonderful match."

Venus's semi-final was a much more subdued affair as she outclassed Safina one from the moment she settled into her big-hitting groove, winning the first nine points of the match and breaking the Russian's service in the process.

Safina simply could not cope with the Williams serve, with one ace in the third game clocking in at 124mph, the fastest in the women's tournament.

It became a lesson in intimidation and when Venus promptly broke the Safina service at the start of the second set the match essentially was over.

She said: "This is my eighth final and it is a dream come true to have another opportunity to hold the plate up.

"I was able to stay focused and I have so much experience on this court. But the hardest part has to come, to play Serena in the final."