The defending champion Russian, seeded second this year, survived a nightmare start to hold on to her crown for at least another day with a 0-6, 6-4, 6-3 win over tough Jelena Jankovic in a compelling quarter-final tie.
World number three Azarenka, meanwhile, reached her first semi-final at Roland Garros when she defeated friend and former doubles partner, Maria Kirilenko of Russia, 7-6 (7/3), 6-2.
Sharapova and Azarenka have played each other 12 times with the Belarusian 7-5 ahead, although it will be their first meeting this year.
"She played such a great match from the beginning and was very aggressive," Sharapova said of her opponent.
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"I knew after the first set that I had to change things around. I just had to erase the chapter and move forward. I still felt I was in the match and I broke her in the first game (of the second).
It was just the fourth time in her Grand Slam career that Sharapova had lost a set 6-0, but she could have no complaints, having committed 20 unforced errors to just two from Jankovic.