Richard Williams waited until the conclusion of the quarter-finals of the women's singles before adding his voice to the growing consensus that daughters Venus and Serena will contest Saturday's final at Wimbledon.

If he had harboured any doubts the two girls would go head to head for the championship for a fourth time — Serena beat her older sibling in 2002 and 2003, while Venus triumphed last summer — they were dispelled yesterday as he watched two one-sided singles matches and again today as there was more of the same in the doubles.

On her own on Court No1, Venus lost just three games against 11th seed Agnieszka Radwanska, of Poland. Because the rout — her 19th straight victory at the All England Club — lasted only 68 minutes, Williams Snr had time to move on to Centre Court to see Serena dismantle
Victoria Azarenka, of Belarus, the eighth seed, for the loss of five games in 73 minutes.

If the sisters are sensational playing singles, they are deadly as a pair. Today, the fourth seeds beat 12th seeds Anna-Lena Groenefeld, of Germany, and her American partner Vania King 6-2, 7-5 to reach the semi-finals.

“Both are playing super well,” said Williams Snr. “They're playing the Williams way. And when you're playing the Williams way, it's very difficult for anyone to touch you.”

The Williams way? “We have a great game,” said Serena, the second seed who tomorrow goes up against Russia's Elena Dementieva. “We have strong serves, we have pretty good returns, we both move pretty well. We're just solid court players.”

Of course, there is more to it than that. Venus, the five-times Wimbledon champion and third seed who plays world No1 Dinara Safina in the semi-finals, highlights the aggression in her personal armoury.

“I'm just very aggressive,” she said. “And I do have strategy. Maybe it doesn't look like it, but I do. That's my secret weapon — it doesn't look like I'm thinking but I am.”

Serena, the US Open and Australian Open champion, doesn't have a secret weapon as such but she is willing to share two of the secrets of her
extraordinary success. “Hard work and good
training,” she said.

“I feel like I've been blessed to have some talent but I work hard at what I do, to turn that
talent into more talent.”

It was pure instinct that enabled Serena to steer Venus through today's doubles. At the net she reacted like lightning to everything Groenefeld and King could throw at her.

Having raced through the first set in 35 minutes, the Williams sisters were made to work a little harder in the second as their opponents fought back from 4-1 down to go level at 5-5. But it was only delaying the inevitable.

Next up are the No1 seeds Cara Black, of Zimbabwe, and Liezel Huber, of the United States, who this morning beat 11th seeds Nuria Llagostera Vives and fellow Spaniard Maria Jose Martinez Sanchez 4-6, 6-3, 6-0.

What does the opposition make of the Williams phenomenon?

Dementieva, who lost to Venus in last summer's semi-finals, believes it is impossible to compare her style with that of the younger Williams sister. “Serena's biggest weapon is her serve,” said the fourth seed. “Serena is very powerful on her first serve and her backhand is one of the best shots in her game.”

The big difference between Venus and Safina is mental strength. Venus has it, Safina doesn't, although the Russian takes comfort from the knowledge that she won their last meeting, on clay, earlier this year.

Safina said: “Definitely grass is her best surface. She loves playing here at Wimbledon. But I beat her in Rome, so I know her weapons and I have my weapons, too.”

They don't include an electric start, nor a serve which saw her concede 15 double faults against
German Sabine Lisicki yesterday.

Safina said: “Especially against Venus, I cannot have another slow start because here she is so fast. I have to go on court pumped from the first point.”