All the favourites for the Olympic women's modern pentathlon were off the early pace after the initial shooting phase on Friday.
Instead Switzerland's Belinda Schreiber was the leader after the first round, having scored 188 out of a possible 200 points in the 10-metre pistol shooting competition.
Canada's Monica Pinette and Belarus's Anastasiya Samusevich were just behind with scores of 187 each.
Amelie Caze, crowned world champion in Budapest in June, was down the 36-women field in 23rd place, but the Frenchwoman is known to be a much stronger swimmer and showjumper, two of the other disciplines in a five-event, one-day, competition which also features fencing and a finishing 3,000m run.
Egypt's Aya Medany, the world championship silver medallist was ninth while Katy Livingston of Great Britain, third in Hungary, was 19th.
Sheila Taormina set a record just by taking her first shot. The 39-year-old American is competing in a record-breaking third different sport in her fourth Olympic Games.
She won gold as a swimmer in the 4x200 metres relay at the 1996 Games in Atlanta, before featuring in the triathlon in Sydney in 2000 and again four years ago in Athens.