Elisa Di Francisca took gold in a spectacular Italian clean sweep of the women's individual foil on the first day of fencing competition at the ExCeL arena.
The 29-year-old beat Arianna Errigo 12-11 in a final that went to sudden death after 38-year-old star Valentina Vezzali, bidding for an historic fourth consecutive gold in the event, had been forced to settle for bronze in even more dramatic fashion.
Vezzali, who carried Italy's flag at the opening ceremony the night before, came back from the huge disappointment of losing her semi-final to Errigo to beat Nam Hyun-hee, the Korean she beat in the 2008 final, in overtime.
The police officer, whose incredible Olympic story began with a silver in Atlanta in 1996, trailed Nam 12-8 with only 13 seconds remaining, but levelled with a second to go and then triumphed.
After breaking down in tears and kissing the piste Vezzali said: "I wanted to win a fourth (gold), but I go home with the bronze - it's ok.
"Today was very difficult. Five Olympic Games and all the time the pressure is more and more."
No woman has achieved four straight golds in any individual Olympic competition - and the only men to have done it are Carl Lewis in the long jump (1984-96) and fellow American Al Oerter in the discus (1956-68).
Her third place means world number one Vezzali equals compatriot Giovanna Trillini with a women's record eight medals in the sport and Italy are now even stronger favourites for team gold on Thursday.
The last four was contested by the world's top four, but the semi-finals were both upsets according to the seedings.
Third-ranked Di Francisca came from 9-5 down with under a minute left to level and beat Nam eight seconds into sudden death.
She was then 11-8 behind to Errigo with 37 seconds left, but scored three times in the space of three seconds of action and needed only one extra second to take the title.
Di Francisca had also been given a real scare in the last 16 by Germany's Carolin Golubytskyi, who led 8-3 and was still 8-6 ahead when she was felled by a blow to her neck and needed treatment for nearly five minutes.
"It was not fair - she touched and then hit me with her (hand) guard. It was a boxing hit," Golubytskyi said after getting back on her feet and losing 15-9.
"It changed the rest of the fight. It upset me. I was not mean enough - I'm not a mean person. I've got four years to work on this to become stronger."
Di Francisca said: "I'm very, very happy now, but in the final I was afraid to win and it was very difficult in my head.
"She's very, very strong. I know her and she knows me."
Told that Vezzali intends to go on to Rio in 2016 - she will be 42 then - the new champion told Press Association Sport: "I'm not surprised. Fencing for her is life and she will be dangerous always."
Vezzali admitted she did not sleep much following the opening ceremony because of the adrenalin of leading the Italian team out, but on targeting yet another Olympics she stated: "Now I have a big motivation to continue.
"When there is problem (she meant her performance in losing the semi-final) I want to resolve it."