Nicola Spirig of Switzerland edged out Swede Lisa Norden in a photo finish in a dramatic end to the women's triathlon in Hyde Park.
Britain's Helen Jenkins was in a leading pack of five on the 10km run before being dropped by Spirig, Norden, Australia's Erin Densham and Sarah Groff of the United States in the closing stages.
Spiring and Norden then sprinted for the line and could only be separated by a photo finish. Densham claimed the bronze ahead of Groff, who had to settle for fourth place while Jenkins finished in fifth place.
Ireland's Aileen Morrison was 35th after the swim but all hope of making progress was quickly halted when, on very slippery conditions, she fell off the bike on the very first lap.
She struggled to make progress thereafter and came home in 43rd position, 8:28 behind Spirig.