Vezzali celebrates her third gold medal in three years
Italy's Maria Valentina Vezzali made it three individual foil gold medals from three consecutive Olympics with another triumph in Beijing.
She took the lead on a touch with four seconds left and held off South Korea's Nam Hyunhee 6-5 to take the top prize.
Margherita Granbassi won the bronze, her first Olympic medal to deny fellow Italian Giovanna Trillini her eighth.
Britain's Martina Emanuel was defeated 15-7 by Erinn Smart of the United States and did not make the finals.
The 34-year-old world number one Vezzali has now won more individual Olympic golds than any other fencer.
She began the final in total control, using cat-like moves to patiently set up her attacks and go up 3-0.
The fleet-footed Nam then managed to avoid several charges from the Italian and hit on the counter-attack to turn the score around and set up a potential upset.
Vezzali was down 5-4 with 41 seconds to go and lost a video replay challenge, but she charged ahead and tied the score, setting up the tense finish.
"I have to first off all thank my little boy Pietro, who is waiting for me," she said. "I always gave my heart and soul to this sport."
As the time hit zero, Vezzali's coach ran on the piste, picked the champion up and carried her around the venue on his shoulders.
The 34-year-old beat compatriot and world champion Margherita Granbassi en route to the finals.