By Alan Baldwin

RIO DE JANEIRO (Reuters) - Kosuke Hagino won the men's Olympic 400 meters individual medley, and the first swimming gold medal of the Rio Games, on a stellar night for Japan on Saturday.

Hagino, the bronze medalist in London in 2012, won with a time of four minutes, 6.05 seconds to end a U.S. stranglehold on the event dating back to 1996 and give the Tokyo 2020 Olympic hosts plenty to celebrate.

Chase Kalisz of the United States, who had been fastest in the afternoon heats, finished second and 0.70 behind.

Japan's Daiya Seto took the bronze -- the first time since 1956 that two Japanese have won swimming medals in the same race -- with Britain's Max Litchfield fourth.

Hagino's time was the third fastest ever and the fastest by a non-American swimmer.

Olympic champion Ryan Lochte of the United States did not qualify for the event at the U.S. trials and nor did world record holder Michael Phelps, the winner in 2004 and 2008. American Tom Dolan won the event in 1996 and 2000.

Hagino's win made up for missing out on the world championships last year due to injury after he fell off his bike at a training camp, a gold that Seto won in his team mate's absence.

"I couldn't compete in the world championships last year but I enjoy this Olympic Games," he said.

Seto led for the first 100 meters, covering the opening 50 meters of the butterfly leg inside world record pace, but Hagino was ahead at the 150 mark and led the rest of the way with Kalisz passing Seto at the end of the breaststroke leg.

The gold was Japan's first in swimming since Kosuke Kitajima in the men's 200m breaststroke at the 2008 Beijing Games.

"I did an incredible time. Obviously I am disappointed it was not enough," said Kalisz, who has trained with 18 times gold medalist Phelps.

"I am more driven than ever and I can't wait to get back training and hopefully make (the next Olympics in) Tokyo. That's my next goal right now."

(Reporting by Alan Baldwin; Editing by Greg Stutchbury)