Flora Duffy finished eleventh in the ITU Olympic Qualification Event — a dress rehearsal for next summer’s Olympic Games — at Copacabana Beach in Rio de Janeiro yesterday.

The 27-year-old, who won a bronze medal at last month’s Pan Am Games in Toronto, posted an overall time of 2hr 01min 23sec, with Gwen Jorgensen, of the United States, claiming victory to extend her winning streak to an incredible 12 consecutive races.

Duffy’s swim time of 19:31 was seven seconds quicker than Jorgensen’s, while the Bermudian’s bike ride of 1:03:45 was just three seconds slower than the race winner’s.

However, it was in the run where Jorgensen showed her extra quality, finishing in 33:57, which was two minutes and 42 seconds quicker than Duffy’s.

Jorgensen pulled away from Britain’s Non Stanford on the final running section to win by 19 seconds in 1:58:46. Vicky Holland, of Britain, was third in 1:59:27.

With the first three finishers guaranteeing their nations a spot in Rio next year, the US and Britain can start making plans for South America’s first Olympics. Anne Haug’s seventh place also guaranteed Germany a place in the Games.

Jorgensen finished a disappointing 38th at the London Olympics in 2012 after suffering a flat tyre.

Duffy, a two-times Olympian, will hope for better fortunes in Rio should she qualify for the Olympics. At the London Olympics she suffered heartache after crashing in front of Buckingham Palace while leading the chase group.

She also endured misery in Beijing 2008, when she failed to finish because of loss of form and illness. Duffy also competed in Rio at the 2007 Pan Am Games, where she finished twelfth in 2:03:13.

Last week, the results of a five-month investigation into Rio’s waters were released and showed that Olympic venues are rife with disease-causing viruses and bacteria.

The study showed that the spot where triathletes entered the water on Copacabana Beach yesterday had a minimal reading of more than two million human adenovirus per litre — that is 2,000 times the reading that water experts in the US say would be considering highly alarming if seen on beaches in the US or Europe.

Human adenovirus multiply in the intestinal and respiratory tracts of people. These are viruses that are known to cause respiratory and digestive illnesses, including explosive diarrhoea and vomiting, but can also lead to more serious heart, brain and other diseases.