Venue: Roland Garros Date: 24 May - 7 June
Coverage: Live on BBC Red Button, live streaming and daily text commentary on BBC Sport website, updates on BBC Radio 5 Live plus second week commentary on BBC 5 Live Sports Extra. TV coverage on Eurosport.
Ivanovic has struggled for form since winning the 2008 French Open
Defending champion Ana Ivanovic surrendered her French Open crown after a 6-2 6-3 defeat by Victoria Azarenka.
The 21-year-old Serb, seeded number eight, had not lost a set en route to round four but she was comfortably brushed aside by the ninth seed.
Azarenka now meets top seed Dinara Safina, who dropped only her fifth game of the tournament in a 6-1 6-0 thrashing of France's Aravane Rezai.
Maria Sharapova beat Li Na 6-4 0-6 6-4 and next faces Dominika Cibulkova.
Former world number one Sharapova, who has slipped to 102 in the rankings after a long spell out with shoulder trouble, fought back from 4-2 down in the third set to oust Chinese 25th seed Li.
The Russian was struggling with cramp to her left thigh in the latter stages but came through for a victory that keeps alive her hopes of a fourth Grand Slam title.
Sharapova said: "Whatever it takes. Two sets, three sets, two sets and five hours.
"The thigh was just a little sore. It will be OK, we have a day off in the grand slams, so it will be fine."
Her opponent said the Russian's mental strength had made the difference.
"She's strong, so strong mentally. She was always fighting, it doesn't matter what the score was," said Li.
Sharapova's last eight opponent, Cibulkova, is through to the quarter-finals of a Grand Slam for the first time with a 6-2 6-4 win over Agnes Szavay of Hungary.
Szavay beat third seed Venus Williams in the third round, but she conceded five straight games in the second set as Cibulkova went 5-2 up.
The Slovak was broken while serving for the match, but only had to wait a short while to seal a place in her first major quarter-final.
"I felt like I going to cry because I was just so happy," said the 20th seed. "I play tennis for these moments."
Former world number one Ivanovic exits Roland Garros after she was comfortably beaten by Azarenka.
The 19-year-old Belarusian broke twice before taking the first set and although Ivanovic launched a spirited in the second, it was Azarenka who kept her composure to prevail.
"I started really well and felt really good at the beginning," said Ivanovic.
"Then after the third game, actually after (the) first point in the fourth game, I just suddenly started feeling so dizzy and I completely lost my balance.
"Ever since then it was really hard. I struggled with looking up. I started feeling very dizzy, and I was struggling a little bit to find my balance."
Safina continued her prolific run at this year's tournament with a 6-1 6-0 demolition of Rezai.
I honestly feel I can do much better - if somebody pushes me more I can get much more out of myself
The Russian falls just short of the record of Mary Pierce, who conceded four games en route to the Paris quarter-finals in 1994.
For a few minutes it seemed that Safina, bidding for a maiden grand slam title, would not have it all her way against Rezai.
The Frenchwoman, ranked 57 in the world, had two break points in the third game but then ran into a brick wall as all her groundstrokes started rebounding back to her side of the court faster.
Safina shrugged off the first break point with a service winner and Rezai sent a backhand wide on the second.
The Russian, who has only lost once on clay this season, went on to break for 3-1 after benefiting from two double faults by Rezai.
Safina mixed her game with sliced backhands to further unsettle the world number 57 and broke again for 5-1 with a forehand down the line, following on serve to pocket the first set.
Rezai managed only nine points in the second set as Safina peppered the court with groundstroke winners.
She bagged another straightforward victory on her first match point when the Frenchwoman netted a backhand.
"I'm surprised that I've only lost five games in getting to the quarters," said Safina.
"It's not a bad feeling, and I hope if I continue like this I can go a long way.
"I honestly feel I can do much better. I think that if somebody would push me more I still can get much more out of myself.
"Overall, I think I can serve much harder still. I think I'm playing good enough but I still feel like I can do better."