Horton swam a tactically perfect race before holding off Yang in a ding-dong battle over the final lap, just hours after declaring the former Chinese doper a cheat for whom he had neither time nor respect.
It was a massive call to go on the offensive before a big final but the 20-year-old never looked nervous, holding his form to touch the wall in 3:41.55 and earn the first of what should be a golden night for Australia in the pool.
The performance was hailed as a victory for clean athletes over drug cheats, although Horton was magnanimous enough to initiate a handshake with Yang as he stood atop the podium to collect his gold medal and hear the Australian anthem.
“I don’t know if it’s a rivalry between me and (Yang), just me and athletes who have tested positive, I guess,” Horton said afterwards.
Yang, meanwhile, raced through the media mixed zone with his head down and didn’t conduct any interviews.
Horton, the 20-year-old Victorian, had set himself to be a 1500m swimmer but the 400m has delivered in spades. On night one in Rio, there would be no underperforming like London four years ago as Horton clinically executed on the biggest stage of all.
Britain’s James Guy, out in lane seven, had gone out all guns blazing in the opening 200m and hit the halfway mark nearly a second under world record pace. He was always likely to run out of gas, though, after that start and Horton and Yang, having patiently waited for their moment to pounce, soon cruised past him.
They touched the wall for the penultimate time with Horton only fractionally in front and while Yang threatened to run him down in a frantic finish the Australian held him off. (Courtesy Sydney Morning Herald)