Serena Williams faces Victoria Azarenka semi-final

Serena Williams and Victoria Azarenka set up a mouthwatering semi-final clash at Wimbledon as both women powered through their quarter-final matches under the Centre Court roof today.

Williams sent defending champion Petra Kvitova packing in one the most eagerly-anticipated clashes of the tournament so far before second seed Azarenka dispatched Austrian Tamira Paszek in straight sets.

Four-time champion Williams turned on the style on her debut under the Centre Court roof to out-muscle her Czech opponent in a 6-3 7-5 win.

The 30-year-old American used her powerful serve to great effect in the match, sending down 13 aces and winning 86% of her first-serve points in her best performance in the tournament so far.

Williams revealed a pre-match pep-talk from her dad and sister Venus had inspired her to victory against the Czech fourth seed.

"I had a good talk with my dad, he motivated me, and my sister as well," Williams said.

"I had a talk with Patrick (Mouratoglou - Williams' coach) too. It was great. All three of those got me really motivated to do better and be the player that I know I can be.

"I just took to heart what everyone said. I really prayed about it, just to have calmness of mind and just go forward and do the best I can do, whether that's winning or losing."

Kvitova admitted Williams is now her pick to win the championship following her dominant display.

"I think so," the 22-year-old said, when asked if Williams was now the tip to win the tournament.

"I think I didn't play badly, but she just served very well and that was the big difference.

"I can't say it's impossible to beat her because she's human, but I think that's why she is a great champion, because she knows what she needs to play the important points.

"I think it's really tough to beat her."

Meanwhile, Azarenka saw off Paszek thanks to a second set tie-break after the Austrian fired long on match point to win 6-3 7-6 (7/4).

Azarenka said: "The games were really close. At the beginning of the second set we were really holding our serves well.

"It was a close match and there were a lot of long rallies but I'm glad I could manage to win.

"It's a great feeling to be in the semi-final of a grand slam but I still want to go all the way and it still seems so far away.

"There's no better opponent than Serena in the semi-finals so I'm really looking forward to that match."

Eighth seed Angelique Kerber booked her place in the last four with a hard-fought win over fellow German Sabine Lisicki.

Kerber claimed a 6-3 6-7 (9/7) 7-5 win over Maria Sharapova's conqueror after two-and-a-half hours to reach her first Wimbledon semi-final.

It was a rollercoaster battle, and Kerber looked like she had blown her chance when she missed three match points in the second set and then trailed 5-3 in the decider.

But Lisicki faltered when serving for the match and eighth seed Kerber reeled off four games in a row to triumph under the Centre Court roof.

Kerber said: "It's unbelievable, the match was so tough. Suddenly she played unbelievable tennis. I'm very happy to be in the semis here for the first time.

"We have known each other from a young age and it was mentally not easy, but it doesn't matter who you play, you have to play your best and I stuck to my plan and played a very good match I think."

PA