LONDON: When Serena Williams screamed out in pain and crumpled in a heap on Centre Court, Victoria Azarenka could have been forgiven if she started to dream of an unlikely escape from her Wimbledon nightmare.

Azarenka was being given a brutal lesson in grasscourt tennis from Serena during their Wimbledon quarter-final on Tuesday and an injury seemed the only possible way the American second seed could be stopped.

Of course Azarenka wouldn't have wished Serena ill but when it comes to beating one of the Williams sisters in their current mood, it seems best to pray for divine intervention.

Azarenka, the eighth seed, is widely regarded as one of the best hopes to challenge the Williams' dominance, but the Belarussian was made to look distinctly second rate as Serena recovered from her slip to claim a ruthless 6-2, 6-3 victory.

Poland's Agnieszka Radwanska, the 11th seed, fared even worse against defending champion Venus.

Radwanska won just three games as she was crushed 6-1, 6-2 by the five-time Wimbledon winner.

Top seed Dinara Safina, who faces Venus in the semi-finals, and fourth seed Elena Dementieva, Serena's last four opponent, must be fearing the worst already.

On grass at least Azarenka believes the Russian pair will find it hard to stop Venus and two-time champion Serena making it an all-Williams final here for the fourth time.

"You never know what could happen, but I'm pretty sure they're playing very good tennis and they deserve to play in the final and win the tournament," Azarenka said.

"I think they have a lot of more experience because in the top 10 there are more young girls than has been before. They just have a lot of experience. They know how to handle themselves in all of the situations.

"I haven't watched Venus play. But from the results, you can see that she's been winning pretty comfortably.

"Serena played amazing tennis. She was striking the ball so hard and so good. She didn't give me many opportunities. She really showed the unbeatable Serena.

"She's a real complete player. She has every shot and she's very strong mentally.

"She fights until the last moment. I think she just has the whole package, that's what makes her a great champion."

Radwanska admitted playing a Williams sister in top form is completely different to facing any other player on the tour.

"If I'm playing against Serena and Venus when they're playing such a good tennis it's different than other opponents," she said.

"It's very hard to play Venus if she has a very good day. If she's playing good everything is in, so it's just so hard to do anything on the court.

"I saw that Serena's also playing good. It can be the same final as last year for sure."

While the dominance of Venus and Serena has led many to claim the WTA tour is basically a two-woman show, Azarenka insists the other top ten players shouldn't be dismissed just because they often struggle against the sisters.

"Nobody's perfect. Serena still has her up and downs," Azarenka said. "They are just showing a little bit more of an aggressive game.

"But you cannot really say that they are so good and the other ones not so good. I don't think that's fair."