(CNN) -- Dinara Safina continued her remorseless pursuit of a first grand slam title with a 6-1 6-0 demolition of Aravane Rezai as defending champion Ana Ivanovic crashed out in the fourth round of the French Open on Sunday.
Safina shows a look of steely determination as she dispatched Rezai.
Top seed Safina has dropped just five games through her opening four matches after her 6-0 6-0 sweep of Anne Keothavong of Britain in the first round.
But Ivanovic failed to continue her impressive form at Roland Garros as she slid to a 6-2 6-3 defeat to Victoria Azarenka of Belarus.
The eighth-seeded Ivanovic made 20 unforced errors against one of the rising young stars on the circuit and was made to pay the price.
The 19-year-old Azarenka will be playing in the quarterfinals of a grand slam tournament for the first time.
French teenager Rezai did not have such good fortune and soon felt the force of Russian Safina's play in their fourth round match on Philippe Chatrier.
Safina took the world number one ranking this year despite never winning a grand slam.
She lost out to Ivanovic in last year's French Open final and to world number two Serena Williams in the Australian Open title match earlier this year.
In earlier action, 20th seed Dominika Cibulkova of Slovakia also made the last eight as she beat 29th-ranked Agnes Szavay of Hungary 6-2 6-4.
It was the first major quarterfinal for Cibulkova, who served for the match at 5-2 in the second set but was broken by Szavay, who put out Venus Williams in the previous round.
But on her next service game, Cibulkova wrapped up her victory.
Szavay upset third-seeded Venus Williams in the previous round.
Cibulkova will next meet Maria Sharapova in the quarterfinals after the Russian star enjoyed a 6-4 0-6 6-4 win over Li Na of China.
Sharapova is returning to tournament play after a shoulder injury and growing from strength to strength on the French clay.