An all-Williams Wimbledon final remains on the cards after both Venus and Serena posted straight-sets victories in their quarter-finals on Tuesday night.
Venus brought Thai veteran Tamarine Tanasugarn, who had beaten second seed Jelena Jankovic on Monday, back down to earth with a 6-4 6-3 victory while Serena needed just 51 minutes to crush Polish No.14 seed Agnieszka Radwanska 6-4 6-0.
Russian Elena Dementieva, the highest seed remaining in the tournament, did her best to throw away a semi-final berth but eventually progressed in three sets against compatriot Nadia Petrova 6-1 6-7 (6-8) 6-3.
The upset of the day was provided by Zheng Jie, who became the first Chinese player to reach the semi-finals of a Grand Slam tournament by upsetting Czech 18th seed Nicole Vaidisova 6-2 5-7 6-1.
Zheng, who eliminated top seed Ana Ivanovic on Friday, will face the younger Williams sister for a berth in the final.
The Chinese world No.133, in the tournaments courtesy of a wildcard, secured the first set thanks to a double fault from Vaidisova but the Czech won the second after breaking in the 11th game of the set.
Zheng secured two breaks in the decisive set and won through on her third match point.
Venus had little trouble against Tanasugarn, the world No.60. After taking out the first set in nearly an hour, the defending champion's strong serving helped her extinguish any hope of a revival from the Thai outsider.
"I think it has been the key for me in this tournament. Any time I'm down break point, double break or something like that, my serve gets me out of it," she said.
"The challenge this year has been the sun. I've never had to serve in the sun at this tournament. I can't see the ball after I serve. I'm blinded, so it's pretty interesting."
Her sister Serena destroyed Radwanska, a former Wimbledon junior champion and world No.11.
Radwanska retrieved an early break in the first set but from then on it was all Williams. She raced through the first set in 32 minutes then conceded just eight points in the second.
Dementieva's game went into freefall after she raced to a 6-1 5-1 lead against Petrova.
Not known for nerves of steel, Dementieva dropped the next five games and squandered two match points to allow Petrova to level the match.
Dementieva lost to Dinara Safina from a set and 5-2 up in the French Open recently but looked set to erase that disappointment as she raced into a 4-0 lead in the decider.
Petrova broke back to reduce the deficit to 4-2 but this time Dementieva held her nerve to serve out for a rollercoaster victory.
"I'm extremely happy," Dementieva said.
"I'm in the semi-finals for the first time in my life and it's a great feeling."
"I was so tight, it was so close to finishing in two sets and I don't know what happened. Maybe I was thinking about the French Open quarter-finals."
"I was trying to stay positive and aggressive but it was so hard."