(CNN) -- She is gunning for a fifth Wimbledon title and Serena Williams eliminated one of her main rivals Tuesday by knocking out defending champion Petra Kvitova.
Williams won her last Wimbledon crown in 2010 but the No. 6 seed looked in good touch as she triumphed over her Czech opponent 6-3 7-5 in a little under an hour-and-a-half.
The 30-year-old will now face Australian Open winner Victoria Azarenka after the No. 2 seed from Belarus beat unseeded Austrian Tamira Paszek.
In the top half of the draw, Angelique Kerber beat fellow German Sabine Lisicki 6-3 6-7 7-5 to book her first ever Wimbledon semifinal.
The No. 8 seed will now play Polish third seed Agnieszka Radwanska after she beat unseeded Russia's Maria Kirilenko 7-5 4-6 7-5 in a match that was delayed several times by the rain, before being moved to Centre Court.
But of those who are left in the tournament, Williams is by far the most experienced having triumphed at the All England Club in 2002, 2003, 2009 and 2010.
"It feels like a good win," Williams said. "I don't know if it was about dethroning the champion or just going out there and doing the best that I could.
"You can't play a defending Wimbledon champion or Grand Slam champion and not elevate your game. I had to weed out the riffraff and get serious.
"It's not easy to defend your first Grand Slam title, either. I think when I defended my first one I didn't win -- but she did great. She held herself in ultimate class and played her heart out. I don't think I've seen her play that well."
It is only the second time Williams has reached the last four of a Grand Slam since her Wimbledon triumph two years ago. But it was her third win in a row against Kvitova, who secured her maiden major title in London last year.
Despite her performance, Serena said she'd need to up her game if she were to take a fifth crown. "I'm going to have to if I want to win the title. There's a lot of people vying for it still," she added.
Kvitova pointed to Serena's formidable serve as the major deciding factor with Williams winning 86% of those points.
"I think it was a great match from both of us, and I think she just served much better than I did," Kvitova said. "I don't think I played badly, I think she just served very well. In the last game it looked like she did almost four aces.
"Unfortunately I have to leave this tournament in the quarters, but I know I have a lot to build on, and I can be stronger and I can improve everything in my game going forward. I'm looking forward to playing the Olympics here."
Azarenka and Paszek's match was also delayed by bad weather but the Belarusian edged through, setting up a clash with Serena.
"It was a close match it was a lot of long rallies so it was difficult but I'm glad I could manage to win," she was quoted as saying by Wimbledon's official website.
"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 seems so far away! There's no better opponent than Serena in a Grand Slam semifinal so I'm really looking forward to that match."