Richard Williams danced down the aisle adjacent to the royal box like a happy, crazy old fool.

Pointing his finger at his daughter Venus, and jinking from one foot to the other, the all knowing creator of the Williams act had just witnessed his family's Royal Command performance. Having shuttled between Court One and Centre Court in an effort to monitor both of his daughters' quarter-final matches, Richard finished his fraught vigil watching the normally understated Venus shriek her way across Centre Court, following a 118 mph final ace which left a bewildered Martina Hingis still glued to the baseline.

The serve ensured a 6-3, 4-6, 6-4 victory and a semi-final meeting between 20-year-old Venus and her 18-year-old sister Serena, who beat fellow American Lisa Raymond as she has done every other opponent - in straight sets (6-2, 6-0).

The parent-coach, who immediately declared that he was "pleased" and will "not be watching the match" tomorrow, will now be placed in the rare position of plotting the downfall of both of his daughters for a place in the Wimbledon final.

It will be the first time in the professional tennis era that two sisters have met in the singles draw of Wimbledon, and the third time in history that sisters have ever met at all in the championships.

Maud Watson defeated her sister Lilian 6-8, 6-3, 6-3 in the inaugral women's championship in 1884, while Gail Sherriff-Chanfreau beat her sister Carol 810, 6-3, 6-3 in the second round of the 1966 championships. It will be the eighth time that sisters have ever met in a Grand Slam since the game went professional.

Of the two matches, it was Hingis against Venus that really fed on the vitality of the packed stadium. Like Serena, Venus was playing in her first Wimbledon semi-final, but in this instance her biggest rival Hingis was facing her across the net.

From the outset, it was difficult to ignore the bullfight analogy. Williams was knocking down serves of 115 mph and thumping ground stokes at Hingis with all the rage and passion of a boxer threatening to punch herself out before round one.

Every ounce of power from her six feet one inch frame was aggressively concentrated in a blitz of unforgiving ground stokes that would have had most players pinned to the wall under the debenture seats.

But not Hingis. Dressed plainly for the occasion in contrast to the backless warrior robes of Williams, the 19-year-old Swiss player met the American tempest with the cool detatchment of a pharmacist weighing out the ingredients of a prescription.

Williams devoured anything loose or off length and, even when Hingis read the direction, the pace occasionally beat her to the spot. The pitch of Williams' offensive game was such that at times when consideration would have bought much more, she couldn't shake off her murderous urge, booming a number of simple volleys several feet wide of the court. The strength of her game, though, was that she was relentless.

The first set saw three breaks of serve, Williams taking the third in the eighth game to serve out for the set.

The second set was more littered with error, which merely heightened the drama. Five service breaks, culminating in one of Williams' outrageous errors on a forehand drive volley, welcomed Hingis back into the match. That trend continued. The three consecutive breaks in the second rolled into the final set, where there were five more in succession, Hingis losing the fifth game to critically fall a break behind.

Despite the accuracy of her strokes, the Hingis second serve occasionally wobbled as Williams typically went for broke. And that's how it ended. The ace, the shriek and Richard jigging in the aisle.

"That's one of the happiest (times) that I've seen her after a match," said Serena. "I don't know how he (Richard) is (going to work it out). I think he's just going to tell us what we need to work on," she added before going on to declare that there "is no sibling rivalry between us."

"Today I think is one of the best matches I've played in my career to date. I'm feeling very excited, very happy, feel like I can make anything happen," she said.

Serena took just 41 minutes to end Raymond's run in a one-sided contest. In five matches, only one player has taken more than three games from her. Venus, with much the harder run, has at times struggled to close the door on weaker opponents.

"It's been a little tough for me. This is the first time that I've been playing good tennis . . . sure the matches shouldn't have gone that far, but they did," she said. "Our parents told us this would happen, that's what we were working for. It's how we saw it. My parents were really positive. "We were always taught to believe that we were the best, even if we weren't the best. We feel we are the best. As a competitor, there's no way you should believe that someone is better than you."

Richard Williams has always predicted his daughters would dominate. They have always believed him. One will now make the final of the world's biggest tennis event. And there's no rivalry ?