Victoria Azarenka beats Agnieszka Radwanska in Indian Wells
World number one Victoria Azarenka continued her stunning start to the year by thrashing Poland's fifth seed Agnieszka Radwanska in Indian Wells.
The Belarusian powered to a 6-0 6-2 win over Radwanska, who has the second-best record in 2012 after Azarenka.
"I was really impressed with the way I played today," said Azarenka, who has won all 21 of her matches this year.
Novak Djokovic, Rafael Nadal and Roger Federer all made it through to the quarter-finals in the men's draw.
World number one Djokovic dropped his first set of the tournament before seeing off Spaniard Pablo Andujar 6-0 6-7 (5-7) 6-2 and he next faces Spaniard Nicolas Almagro, who beat Tomas Berdych 6-4 6-0.
"In the end I was lucky to get through some points," said Djokovic. "I think I played one of my better sets in the last couple months in the first set but he surprised me with his aggressive approach.
"In the second set I started playing a little bit more defensive and that allowed him to come back into the match but in the third set I regrouped. I managed to stay calm mentally and find my rhythm again."
Federer, who next faces Argentina's 2009 US Open champion Juan Martin del Potro, has been battling flu and a temperature in the ATP event that he has won three times.
He battled past Brazilian Thomaz Bellucci 3-6 6-3 6-4, but said: "I'm still hurting a bit but at least I don't have a massive headache, aches and pains any more.
"That's all gone now. I got maybe a bit lucky but it's taken some time to for me to get better, to be honest. I thought I would see quicker improvements."
Nadal's 6-3 6-2 win over 21st seed Alexandr Dolgopolov came in in just 76 minutes and saw him successfully challenge a call to reach match point, which he won when Dolgopolov hit a forehand long.
"He is very difficult to play against," said Nadal. "He can produce winners from every part of the court. He's a funny player, good for tennis."
The Spaniard next faces Argentina's unseeded David Nalbandian, who came from behind to shock sixth-seeded Frenchman Jo-Wilfried Tsonga 3-6 7-5 6-3.
Radwanska has lost just four times in 2012 but each of those defeats came against Azarenka, who said: "I didn't expect to win that way. I'm proud how I fought hard and played winning tennis.
"I had very good motivation because I knew she's an excellent player, so I had to come up with a great match today.
"I was just really focused on every moment, on every point I played, on every ball I was striking. I didn't really think about the score."
The Belarusian will face Angelique Kerber in the semis after the German shocked French Open champion Li Na of China 6-4 6-2.
The eighth seed, who lost in after one hour 23 minutes, said: "My serve didn't work. The three times I played her before I was getting points on my serve but today was different."