Italy's Elisa Di Francisca won the individual foil Olympic gold at the ExCel Centre after defeating compatriot Arianna Errigo in extra time.
The pair were level at 11-11 before Di Francisca scored the vital point early into the extra minute to seal victory.
Earlier three-time Olympic champion Valentina Vezzali needed extra time to beat Korean Nam Hyun-hee for bronze.
It meant Italy completed a clean sweep in the fencing, winning all three medals on Saturday.
Vezzali was the reigning Olympic champion and was hoping to become the first woman to win four consecutive individual gold medals, but was beaten by compatriot Errigo.
Britain's first three fencers in action were unable to make it into the last 16.
Polish-born Natalia Sheppard and Londoner Sophie Troiano had to fight each other in the first round, but after winning a tense clash 12-9 Sheppard was then crushed 15-5 by France's world number six Corinne Maitrejean.
Anna Bentley lost in sudden death to Canadian Monica Peterson.