Serena Williams lived dangerously before emerging with victory and a place in Wimbledon history.

The two-time champion was forced to produce all her battling qualities to overcome an inspired Elena Dementieva in the longest women's semi-final ever seen at the Championships.

Williams dropped her first set of the fortnight and saved a match point before squeezing through 6-7 (4-7) 7-5 8-6 in an epic duel on Centre Court 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 Williams, who will meet sister Venus, the defending champion, in Saturday's repeat of the 2008 final.

"It was definitely one of my more dramatic victories. I felt like I was down pretty much the whole match so to come out on top was a great feeling.

"I wanted to win really bad. I definitely had to dig deep."

Father Richard Williams had claimed before the match that his daughter "was hitting like a man" and, after being on the end of 20 aces, Dementieva compared her serve to that of the fastest server in the world.

"I wasn't sure if it was Serena or Andy Roddick on the other side," said the Russian number two. "It was 125mph all the time."

With a new-look Dementieva serving equally well, producing some unbelievable groundstrokes to stay in the rallies and underlining her growing reputation as the best returner in the women's game, Williams admitted she had to resort to her big weapon to secure crucial points.

"I always went to my serve," Williams said. "My forehand didn't show up today. I think it went to Hawaii. It's always good to win when one of your strokes is on vacation but, whatever it takes, I need it back."

The warning signs were there when the Williams serve was broken in the first game of the match, but she hit back to take the first set into a tie-break, which Dementieva won 7-4.

The Russian's suspect temperament appeared to surface when she dropped her serve at the start of the second set, but she broke back and was two points away from a 5-3 lead.

Williams responded to the threat by pounding down aces to save two of four break points and eventually took the second set 7-5 to force a decider.

The pivotal moment came when, having broken to lead 3-1, the Russian allowed her opponent to put away a volley to save match point in the 10th game and admitted she had taken the wrong option.

"I feel very satisfied with the way I played," said Dementieva. "The only regret I have is that maybe I should have taken a bit more risk on match point.

"I should have gone down the line because the passing shot is my favourite shot.

"Maybe it was too quick. I didn't see she was moving to cover cross-court. She was very close to the net so down the line or even a lob would have worked."

Despite losing at the semi-final stage for the second successive year, Dementieva was able to derive pleasure from taking part in one of Wimbledon's greatest semi-finals.

"For sure I feel disappointed because it was a very close match but I think the way I was playing is more important than the result," she said.

"It was definitely my best match on grass and that was the best match we've played against each other. It was a real fight from the beginning to end."

The 27-year-old Dementieva, runner-up in the French and US Opens five years ago, is on course to rival Jana Novotna for the longest wait for an elusive maiden grand slam victory but she insists her time will come.

"I don't think that it was my best chance, I don't think it was the last chance," she said. "You cannot think about the final before playing semis.

"I'm going to watch this match again and take some positive things from it and go forward."

Dementieva had won four of her previous five meetings with Williams but admits the sisters raise their game for the grand slam tournaments.

"I think it's two completely different players when she's playing grand slams or she's playing other tournaments," acknowledged Dementieva.

"There is a big preparation time for her and Venus when it comes to the grand slams and they're always ready to play at their best."