China started and finished the day on top of the medal table after taking the first gold of the London 2012 Olympics.
Ye Siling took the honour of being the Games' first gold medallist with a nerveless display in the final of the women's 10 metre air rifle.
The 2008 host nation went on to claim three further golds, with 16-year-old swimmer Ye Shiwen taking top billing following a world record in the women's 400m individual medley.
Team-mate Sun Yang finished first in the men's 400m freestyle final and Wang Mingjuan prevailed in the women's 48kg weight category weightlifting with China's total haul for the day four gold and two bronze medals.
A dominant display in the women's individual foil saw Italy women's fencing team complete the Games' first clean sweep, led by Elisa Di Francisca.
There were medals, too, for their men's archery team and 10m air pistol teams, taking their overall tally to five.
The USA featured heavily on the podium in the Aquatics Centre, picking up a medal of each colour, with Ryan Lochte earning a gold in the men's 400m individual medley.
They sit third in the table having also acquired five medals.
Australia enjoyed their first taste of medal success as their women swimmers caused a surprise by winning the 4x100m relay at the expense of the Netherlands.
Competitors from 19 different nations won medals on a day in which 12 Olympic champions were crowned, either in individual or team events.