Soni smashes world record to claim gold
Soni was a big favourite to win the title after setting a world record of 2:20.00 in yesterday's semi-finals, and fully justified her status with a commanding performance.
The 25-year-old took control of the race after the opening length and touched in a time of 2:19.59, slicing more than four tenths of a second off her previous time. Japan's Satomi Suzuki claimed silver, with Russian Iuliia Efimova taking bronze.
In the second final of the evening, USA's Tyler Clary got the better of defending Olympic champion and team-mate Ryan Lochte in the 200m Backstroke.
Lochte led at the final turn but faded in the closing 50m, allowing Clary to snatch victory in a new Olympic record of 1:53.41, with Japan's Ryosuke Irie claiming silver.
That meant Lochte had to settle for bronze to add to his two golds and one silver from London 2012 so far, with the final of the 200m Individual Medley still to come later this evening.