After the relay, Sun did not return to the pool until the last day of competition to compete in his strongest event, the 1500 metre freestyle. He had qualified for the final with the fastest time. At the initial line-up on the starting blocks, a step-down command was issued because of noise from the crowd, but instead of stepping back, Sun reacted by diving in. The officials ruled the early dive was the result of crowd noise and did not constitute a false start, and Sun was allowed to continue in the competition. He went on to win the race with a time of 14:31. 02, breaking his own world record by over three seconds. He finished over eight seconds ahead of second-place finisher, Canadian Ryan Cochrane. With two gold medals and a team bronze medal, Sun became the most decorated Chinese male swimmer in Olympic history, and the first swimmer to win the 400/1500 double since Vladimir Salnikov at the 1980 Moscow Olympics. Sun completed the last 50 metres of the race in 25. 68 seconds, nearly two seconds faster than Cochrane.