- Williams sisters will meet in the semifinals of Family Circle Cup in Charleston
- Americans will play each other for the first time since 2009 WTA finals
- Sam Querrey brings U.S. level at 1-1 with Serbia in Davis Cup quarterfinal
- Defending champion Czech Republic takes 2-0 lead in Kazakhstan
A new movie portraying their rise to the top of the tennis world will debut next month, but the Williams sisters are already giving it their best promotion after setting up their first head-to-head clash since 2009.
Both won two matches at the WTA Family Circle Cup event in Charleston Friday and will meet in the semifinals, with Serena hoping to defend her title and Venus battling to regain her status after longterm health problems.
Serena triumphed 6-4 6-2 against fellow American Mallory Burdette in their third-round match, with the world No. 1 setting up a rematch of last year's final against Czech Lucie Safarova -- which she then won 6-4 6-1.
Her older sibling Venus was already through to the last four, having battled to defeat U.S. 12th seed Varvara Lepchenko 6-2 4-6 6-2 before cruising to a 6-4 6-4 win over 18-year-old compatriot Madison Keys.
It will be only the third time they have met on clay, and the first time on the latterly green surface of this South Carolina tournament -- which dates back to the beginning of the WTA Tour in 1973 and is the oldest women's professional event.
"It was really motivating to see Venus win today -- I figured if she can win two matches, I have no excuse not to win my two matches," Serena said.
"Venus is the toughest opponent I've ever played. I think she's beaten me the most out of any player. I know her game and she knows my game.
"I know her patterns, she knows mine -- she probably knows mine better than I do. I think it'll be a great match tomorrow."
While Serena has bounced back from blood clots on her lungs after a freak foot injury suffered in 2010, Venus has dropped to 24th in the rankings as she struggles to overcome the autoimmune disease Sjogren's syndrome.
The 32-year-old trails her sister 13-10 in career meetings, and lost their last one at the 2009 end-of-season WTA Championships.
"I've seen her so many times -- hopefully all the times I've sat in those stands watching her will give me a little help," said Venus, who won the 40-year-old tournament back in 2004.
"I'm looking forward to it. Last year in Charleston I fell short and I didn't hold up my end of the bargain and make the semifinals, so I'm glad I took it a step further this year."
They were joined in the last four by Jelena Jankovic, who like the Williams sisters has topped the rankings -- but without winning a grand slam.
The Serbian ninth seed cruised past 19-year-old world No. 114 Eugenie Bouchard of Canada 6-2 6-1 for the 500th victory of her career.
Meanwhile, Novak Djokovic gave Serbia the perfect start to the Davis Cup quarterfinal against the United States as the world's No. 1 men's player defeated John Isner in Friday's opening rubber in Idaho.
The big-serving American had hopes of repeating last year's win over Australian Open champion Djokovic in the ATP event at Indian Wells, but was unable to take advantage of the high-altitude conditions in Boise as he went down 7-6 (7-5) 6-2 7-5.
Djokovic also prevailed when they met in the first round of the Davis Cup three years ago, as his country went on to win the title for the first time.
The Serbians' hopes of going through to the last four may rest on Viktor Troicki, who was beaten in five sets by American No. 1 Sam Querrey in the second singles rubber after being asked to replace the injured world No. 10 Janko Tipsarevic.
Querrey won their 2010 encounter -- a dead rubber as the Serbs had already won through -- and this time came back from 2-1 down to triumph 7-6 (7-1) 3-6 4-6 6-1 6-4 and level the score.
The winner of this tie will next face either Canada or Italy, who were also 1-1 in Vancouver.
Andreas Seppi gave Italy an early lead as he came from two sets down against Vasek Pospisil to win 5-7 4-6 6-4 6-3 6-3 in three hours and 15 minutes, but Canadian No. 1 Milos Raonic beat Fabio Fognini 6-4 7-6 (7-4) 7-5.
Davis Cup titleholder the Czech Republic took a commanding 2-0 lead away to Kazakhstan.
With top-ranked Czech Tomas Berdych absent in Astana, world No. 63 Lukas Rosol came from behind to beat Andrey Golubev 4-6 6-4 6-2 7-6 (8-6) and
No. 94 Jan Hajek crushed Mikhail Kukushkin 6-3 6-2 6-4.
The Czechs can wrap up the best-of-five tie in Saturday's doubles rubber, which would set up a match with either France or Argentina.
That quarterfinal was tied 1-1 after the opening day in Buenos Aires, as world No.8 Jo-Wilfried Tsonga battled to overcome 71st-ranked Carlos Berlocq 4-6 6-2 6-3 5-7 6-2 in the opening match.
World No. 19 Juan Monaco, Argentina's No. 1 in the absence of Juan Martin del Potro, gave his country a lifeline by beating 13th-ranked Gilles Simon 7-6 (7-2) 6-2 6-4 on the red clay.