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.