Second seed Serena Williams recovered from match point down to beat Russian fourth seed Elena Dementieva 6-7 7-5 8-6 in a nailbiting semi-final at Wimbledon on Thursday.

In a tournament where spectacular tennis has been conspicuous by its absence from the women's draw, the two produced a semi-final worthy of the name with a riveting display of power-hitting from the baseline and wily court craft.

Serena fulfilled her part of the family bargain by reaching the final, where she might meet sister Venus for a fourth time should the reigning champion beat top-seeded Russian Dinara Safina later on Thursday.

"Elena played so well and we gave the crowd a wonderful match," Serena said in a courtside interview.

Both players got off to a nervous start, each losing their opening service games, before the Russian became the first player to take a set off the American at the All England Club this year by winning the tiebreak 7-4.

Serena levelled the match when a series of aces got her out of trouble when serving at 6-5 in the second before Dementieva, the Olympic singles champion, broke to lead 3-1 in the decider.

The Russian missed match point when a slight netcord helped a Williams volley into play when the second seed served at 4-5.

When asked about her thoughts as the Russian held a point for the match, Serena said: "I thought 'ace', ok it's my serve if I can just stay calm and try and think positive." The American then broke to lead 7-6 and duly held serve to book a place in her fifth final after a two hour and 49 minute thriller.