Wimbledon, England -- (Sports Network) - For the third time in seven years the mighty Williams sisters -- sixth-seeded Serena and seventh-seeded Venus -- will square off in an all-sister, all-American final on the Wimbledon grass.

The former world No. 1 Serena got past Chinese wild card Jie Zheng 6-2, 7-6 (7-5), while the former top-ranked Venus handled fifth-seeded Russian Elena Dementieva 6-1, 7-6 (7-3) on the famed Centre Court at the All England Club. Serena was forced to wait out a pair of rain delays on Day 10.

The powerful sisters battled in finals here in 2002 and 2003, with Serena winning both matchups.

Serena is 8-7 lifetime against her older sister, including 2-1 at Wimbledon. Venus topped her younger sister in the semifinals here eight years ago. Serena has won five of their nine Grand Slam meetings, with all five wins coming in finals. The only major final won by Venus between the two came at the 2001 U.S. Open.

The eight-time major titlist Serena beat Venus at a hardcourt event in India earlier this season.

"She's a tough opponent," Serena said of Venus. "I think she'll be the toughest person I've played. I'm excited."

"It's every Williams for themself," Venus said.

On Thursday, Serena topped Zheng in 1 hour, 25 minutes by blasting 14 aces, compared to zero for the Chinese, and breaking Zheng three times, compared to only one break for the surprising wild card. Rain delayed action twice, with Serena leading 5-2 in the first set, and again, with Serena up 6-2, 4-5.

In the second-set tiebreak, Zheng dumped a second serve into the net on match point to send Serena on her way.

"She definitely pushed me," Serena said of Zheng. "Unbelievable, and not only that she played a great game. She played like she had nothing to lose and she didn't."

Serena is now 2-0 lifetime against Zheng, having also beaten her in the opening round here at Wimbledon four years ago. The hard-hitting American is also now 4-1 in her career Wimbledon semis.

Zheng, who will turn 25 on Saturday, is the first-ever Chinese, male or female, to reach the final four at a Grand Slam and is also the first wild card to land in the semis at the All England Club.

The Venus-Dementieva match was never in doubt, as Venus pounced on Dementieva for a 4-0 lead in the first set, and wound up winning eight of the first nine games for a commanding 6-1, 2-0 advantage. She converted on her first match point when Dementieva netted one final weak forehand.

The former top-ranked Venus moved on in 1 hour, 42 minutes, as she broke Dementieva's suspect serve four times while only being broken once.

The now seven-time Wimbledon finalist Venus is 6-2 lifetime against Dementieva, including a victory in the gold medal match at the 2000 Olympic Games in Sydney.

The 26-year-old Dementieva is a two-time major runner-up and was appearing in her first-ever Wimbledon semifinal and her fifth career major semi (2-3).

The six-time Grand Slam champion Venus is now 7-0 in her Wimbledon semis and 57-7 overall in 12 trips to the All England Club. She defeated France's Marion Bartoli in last year's finale and also titled here in 2000, 2001 and 2005.

The 28-year-old Venus is 6-6 in her career Grand Slam finals, including 4-2 at Wimbledon. She owns 36 titles in 58 career finals and will perform in her first final of 2008 on Saturday.

The 26-year-old Serena owns 31 career titles, including three already this year, and is 8-2 in her previous Grand Slam finals. In addition to her back- to-back Wimbledon titles in 2002 and 2003, she was the 2004 runner-up here to Maria Sharapova.