American gymnast Carly Patterson ruined Svetlana Khorkina's hopes of a fairytale end to her career by claiming gold in the women's all-round event.
The 25-year-old Russian, three times all-round world champion, had hoped to round off her career with the Olympic title which had always eluded her.
But Patterson performed solidly and her excellent floor routine secured gold.
Britain's Beth Tweddle's hopes were dashed with a fall on the beam and she finished 19th, with Katy Lennon 21st.
China's Nan Zhang sneaked into bronze ahead of Russian Anna Pavlova.
Khorkina had been hoping to become the first non-teenager to win the Olympic title since 1968.
The reigning Olympic asymmetric bars champion had suffered mishaps in Atlanta and Sydney and Athens was her final chance to clinch the all-round title.
The Russian led at the halfway stage but slipped back to second after the beam, her least favourite discipline, allowing Patterson to take pole position.
And the 16-year-old American, who had qualified in first place for the all-round event, secured gold with an acrobatic performance on the floor.
Patterson is the first American woman to win the all-round title for 20 years and marks a USA double, after Paul Hamm claimed the men's event on Wednesday.