Nicola Spirig of Switzerland has won the gold medal in a stunning finish to the women's triathlon at the Olympics.

Spirig held off Lisa Norden of Sweden right on the line to claim gold in 1 hour, 59.48 seconds. The pair were given the same time, but Spirig was declared the winner on a photo finish.

Erin Densham of Australia took bronze on the course through Hyde Park in central London.

Spirig initially pulled away in the last 50 meters but only just won after a very late burst from Norden nearly took her past the Swiss right at the very end of the race.

All three medalists collapsed, exhausted, at the finish.