Sharapova smacked a service return into the net on the first and could only watch in wonder as Errani drilled a spectacular forehand winner on the next.
However, the Russian second seed was determined to live up to her top billing and won the set on the next game by belting a backhand winner down the line.
The second set started like the first, with Sharapova breaking before romping to a 4-1 lead.
But the Italian was determined not to go out without a fight and remained undaunted even when Sharapova brought up her first match point by hitting a brilliant forehand on the run.
She forced Sharapova into a forehand error to get back to deuce, then earned a break point by snaring Sharapova with a dropshot.
Sharapova hit back with a thunderbolt backhand winner and after seeing another matchpoint evaporate with yet another Errani dropshot, she brought up a third with an ace.
Image: Russia's Maria Sharapova reacts as she defeats Italy's Sara Errani during their women's final match in the French Open tennis tournament at the Roland Garros stadium in Paris, Saturday, June 9, 2012.