Serena Williams will face big sister Venus for the third time in a Wimbledon Final, after ending wildcard Zheng Jie's hopes of becoming the first Chinese player to reach a Grand Slam Final on Thursday.

Serena — who beat Venus in the 2002 and 2003 finals — had to dig deep to beat a battling Zheng 6-2, 7-6 (7/5) and will seek a ninth Grand Slam title when she faces her 28-year-old sister, who in turn will be chasing a fifth victory here.

The 26-year-old Serena, 11 kilos heavier and more than 11cm taller than the Chinese, had too much brawn for the world number 133, who had made her mark by knocking out top seed Ana Ivanovic in the third round.

"She pushed me and really played a great match," said Serena of an opponent she had comfortably defeated in the first round at NW19 four years ago.

Zheng was left to regret a great opportunity to take the semifinal to a decider when she held set point in the 10th game of the second set, but Williams was able to call on her powerful smash to rescue herself.

"Probably I was thinking too much about the fact that it was set point and I didn't take it," Zheng confessed, although she declared herself happy with the way she performed on Centre Court.

"I knew there were millions and millions of people watching me back home and I really wanted to win. But overall I was satisfied with my performance today," she added.

"Her serve was too big, especialy on grass. Maybe on another surface I would have had a chance to win."

Serena added: "She played like she had nothing to lose. I was able to hit a smash on that set point. I didn't really want to go into a third set.

"I'm looking forward to playing Venus in the final. She'll be the toughest opponent I have faced."

Serena broke the 24-year-old Zheng in the first and fifth games of the opening set as the American stormed into a 5-2 lead before a 40-minute rain break gave the Chinese time to compose herself.

But it was business as usual on the resumption, as Williams served another love game to wrap up the set.

Zheng gave herself a glimmer of hope by breaking Williams to lead 4-2 in the second set, but the American stormed back in the next game and then held to level the set at 4-4.

Another rain delay, this time for 80 minutes, followed at 5-5 and when the players returned Zheng had a set point in the 12th game which Williams saved.

Williams raced to 5-2 ahead in the tie-break before a gallant Zheng pulled level to 5-5.

But the Chinese girl's nerve deserted her when she double-faulted on match point.

Earlier, Venus — the elder of the Williams sisters — beat Russian fifth seed Elena Dementieva 6-1, 7-6 (7/3) to reach her seventh singles final at Wimbledon.

The defending champion was given a tough workout in what was a slug-fest in the second set, but she always looked to have a little in reserve against an opponent making her first appearance in Wimbledon's Last Four.

"She is a similar player to me with a lot of power so I knew I'd have to do what we both do a little better," Venus said. "It was important I managed to get ahead in the tie-break and not let it go."

Williams Senior also brushed aside suggestions that matches between the sisters are rarely classics because of a perceived lack of competitive edge — insisting her close relationship with Serena in no way impinged on her desire to win another title here.

"Our goal is getting to the final and from there it is every Williams for themselves," she said.

Dementieva, meanwhile, admitted she had struggled to cope with the quality of Williams's tennis in the opening set.

"She started really well, she was dominating and putting a lot of pressure on my serve," said the Russian.

"She likes to hit hard, she's got a good serve and it is an excellent surface for her. But she does get tight at times, so I was just trying to make her play and keep the ball in play and that's what happened.

"It was a completely different game in the second set," she added.

For a player who frequently struggles with the tennis equivalent of the yips, Dementieva's decision to serve first after winning the toss was unexpected.

As it turned out, it was also unwise. Inside a minute, the Russian found herself 0-40 down, Williams claimed the break at the second attempt and that set the tone for a one-sided first set.

Dementieva gave a better account of herself in the second, rallying from 0-2 down and then matching her opponent blow for blow until the tie-break, in which Williams was always in control, finally bringing proceedings to a halt after one hour and 41 minutes on Centre Court.

AFP