Japanese swimmer Kosuke Hagino's motto

Kouske Hagino

Tokyo: Don't be fooled by Kosuke Hagino's quiet demeanour and toothy grin - the Japan swimming sensation plans to usher boyhood hero Michael Phelps into retirement at the Rio Olympics.

Kouske Hagino

The 21-year-old, who pipped Phelps to take bronze in the 400 metres individual medley behind gold medallist Ryan Lochte in London four years ago, is targeting double gold in Brazil. "I was lucky to (win a) medal in London," Hagino said. "But this time there will be no luck involved."

Ten years younger than Phelps and Lochte, Hagino has his sights set on a 200m and 400m individual medley double. Phelps completed an astonishing hat-trick in the 200m medley in 2012, defending the title he won in Athens and Beijing.

But the Japanese gold medal hope has posted this year's quickest time in the event and the American superstars will be absent from the 400m.

Different feeling
"It's a totally different feeling to four years ago," said the 2014 swimmer of the year.

Japanese swimmer Kosuke Hagino has his sights set on a 200m and 400m individual medley double. Pic/Getty Images

"The aim will be to win gold in the 200m and 400m medley, no question." Hagino, poised to emerge from the shadow of countryman Kosuke Kitajima after the former Olympic champion failed to qualify for Rio, will also be a decent bet to win a medal in the 200m freestyle and 4x200m freestyle relay.

His 200m freestyle victory over Chinese Sun Yang was one of the highlights of the 2014 Asian Games, where he won four gold medals, only to be halted after he fell off a bicycle and broke his elbow.

Hagino makes no secret of his admiration for Phelps - the most decorated Olympic athlete of all time with 22 medals from three Games, 18 of them gold. "It's just a real privilege to compete against him," said Hagino.

"I watched him on TV when he won eight gold medals in Beijing. Even if I beat him, I'll never be like Phelps." Brazilian Thiago Pereira, who edged Hagino for silver behind Lochte in the 400m medley in London, will also be a threat at his home Olympics.

But in Japan, the Olympic swimming competition is being billed as Hagino versus Phelps. Dwarfed by six-footers Phelps and Lochte, Hagino stands at just five feet, nine inches (1.75m).

"It will come down to mental toughness and squeezing every last drop out of your body," said Hagino.

"To hang in there over the last 15 metres. Phelps and Lochte have longer arms than me," he added. Hopefully with my little body I can be a head in front at that point."