The 24-year-old limbered up for his three individual events with a powerful 47.26sec opening leg to set up his team-mates, who brought it home in the third-fastest time ever.
Zach Apple touched in 3:08.97 after Dressel’s start followed by sizzling swims from Blake Pieroni and Bowen Becker, with Italy (3:10.11) and Australia (3:10.22) in the minor placings.
The United States, who have won 10 of the past 13 men’s 4x100m relay golds, were competing without Michael Phelps for the first time since the 2000 Sydney Olympics, and Dressel acknowledged they had a point to prove.
“It feels great,” he said. “We knew we had a huge target on our back. It feels nice, I’d say we dominated that pretty well. “We’re never going to doubt ourselves, that’s how Team USA works. We had a couple of people rule us out and we’re never going to take that.”
