The 17-year-old Russian toppled the 1999 champion and fifth seed Lindsay Davenport 2-6, 7-6 (7-5) and 6-1 to enter the final.
In the Saturday's final, Sharapova will meet two-time defending champion, top seed Serena Williams, who beat No.4 France's Amelie Mauresmo 6-7 (4), 7-5, 6-4.
Before Maria Sharapova, only Martina Hingis entered the final at 16 and won the title in 1997.