Kosuke Hagino was just 17 when he beat both Michael Phelps and Ryan Lochte, two of the world's all-time best swimmers, to win the bronze medal in the 400m individual medley of the 2012 London Olympic Games. Over the last four years, the young Japanese swimmer has only grown from strength to strength.

In the meantime he racked up seven medals including four gold medals at the Incheon Asian Games and a few more from the Pan Pacific Games later that year. Now at 21, Hagino is tipped by many to be the next big thing in all-round swimming. On Saturday night at the Olympic Aquatic Centre in Rio, Hagino proved why he is regarded so highly.

Hagino grabbed the gold in 400m individual medley clocking 4min 6.05seconds, beating USA's Kalisz Chase by 0.70 seconds and ending USA's dominance in the event which dated back to 1996. "I'm thrilled to be honest. But I've got a few races left so I want to stay focused," the baby-faced swimmer said at the press conference later, admitting that he is relieved to have knocked down his first target. "A lot has happened in the last four years. It wasn't all

smooth sailing."

Having already got one over Phelps four years ago, the young Japanese swimmer will have his chance to beat his idol yet again when they meet in the 200m medley on Wednesday.

"I grew up watching those two (Phelps and Lochte] compete. I wanted to become a swimmer like them. In the 200 metres individual medley I have an opportunity to race against them and I'm looking forward to it," said Hagino, who set the fastest time by a non-American swimmerin the 400m medley.

While Hagino announced himself as a future star of swimming, veteran Kantika Hosszu of Hungary redeemed herself in emphatic fashion by smashing the women's 400m world record and grabbing the gold which took four editions in coming. Dubbed the 'Iron Lady', Hosszu has five world championship titles to her name, yet she had to go home from the last three Olympic Games without a single medal.

On Saturday night, however, she was bent on breaking that drought. The 27-year-old powered her way through to the end as her competitors kept falling behind, with the Hungarian eventually winning by more than 4.79 seconds and breaking the world record by 2.07 seconds.

"I've been chasing that world record for some time now," Hosszu later told reporters after having wrapped up her muted celebration with just a puff of the cheeks and hands raised skywards. "It's been over seven years that I have been thinking about it. 1 feel like I proved myself, not just to other people but to myself. A lot of people thought I would break under the pressure but it was just fun. ”

If the Hungarian can keep having fun like this, it won't be a surprise if she smashes four more world records at the Olympic Aquatics Centre in Rio.