Murray was the only top-eight seed who failed to reach the quarters and the tournament is building toward a thrilling crescendo.
Rafael Nadal remains atop the Yahoo! Sports Australian Open power rankings, having hardly been stretched on his way to the last eight.
However, Williams is still very much the woman to beat and has high hopes of adding yet another Grand Slam title to her collection.
1. (2) Rafael Nadal: Twelve straight sets won without even being taken to a tiebreak. QF: vs. Gilles Simon.
3. (5) Fernando Verdasco: Big serve is finally matching devastating ground game. QF: vs. Jo-Wilfried Tsonga.
5. (-) Jo-Wilfried Tsonga: Last year's finalist is lurking dangerously again. QF: vs. Fernando Verdasco.
6. (7) Juan Martin Del Potro: Big chance to show he belongs with the elite. QF: vs. Roger Federer.
7. (6) Gilles Simon – Through to a Slam quarterfinal for the first time. QF: vs. Rafael Nadal.
8. (8) Andy Roddick: Aiming to reach his first Slam semi in two years. QF: vs. Novak Djokovic.
1. (1) Serena Williams: Edging closer to a fourth Australian Open title. QF: vs. Svetlana Kuznetsova.
5. (5) Jelena Dokic: Aussie star wants to keep the fairytale run alive. QF: vs. Dinara Safina.
6. (7) Carla Suarez Navarro: Conqueror of Venus Williams keeps marching on. QF: vs. Elena Dementieva.
7. (-) Marion Bartoli: Best Slam performance since reaching the 2007 Wimbledon final. QF: vs. Vera Zvonareva.
8. (-) Svetlana Kuznetsova: Out of form and fortunate to have avoided elimination. QF: vs. Serena Williams.