The American-based swimmer took the lead in the butterfly and extended it in the backstroke with the Australian Tom Fraser-Holmes the closest.
However, Scot Daniel Wallace made his move on the breaststroke return, leaving it down to a freestyle sprint that saw both Wallace and the Australian pass Rousseau, who claimed the bronze in 4:13.09.
Wallace, who had set a new Games record of 4:11.04 in the morning heat, was 0.16 second slower in earning his gold, with Fraser-Holmes finishing in 4:12.04 for silver.
“I was there to win the race in the last 50, but somehow it all fell apart,” said Rousseau.
“Obviously I swam to win the gold. Sometime it doesn’t just happen.
“That’s how I swim, I go out to take control from the start, but perhaps when you go out too fast it catches you in the final 50m,” said the sports management student from Gainsville, Florida.
“It’s about learning how to swim the race perfectly. It’s a tough thing to do but I was just happy to pull through to a medal on the big stage,” added Rousseau, who has clocked a 4:11 in lesser competition.
“My best time would have won the race, but then in poorer competition I have greater control over the race for longer. Here the competition is tougher. It’s a good way to learn the pacing.”
His bronze provides Rousseau, who gave the crystal bowl awarded with the medal to his brother in the crowd, with a good foundation for Rio 2016, where his focus will be to return to the podium.
– Sapa
Download our app and read this and other great stories on the move. Available for Android and iOS.