Hungary’s Hosszu smashes world record

This triumph was especially sweet for Hosszu, who had captured nine medals including five golds at the world championships but never won an Olympic medal.

Katinka Hosszu of Hungary celebrates after winning the gold medal.   -  Getty Images

After repeated frustration on the sport’s biggest stage, Katinka Hosszu of Hungary crushed the world record in the women’s 400-metre individual medley on Saturday night to make the first Olympic gold medal of her career.

This triumph was especially sweet for Hosszu, who had captured nine medals including five golds at the world championships but never won an Olympic medal. She defiantly pumped her chest before breaking into a huge smile. Elizabeth Beisel of the U.S., the silver medalist at the 2012 London Games, finished sixth.

Also on a late night of swimming to kick off the Rio Games, Japan’s Kosuke Hagino ended American dominance in the men’s 400-metre individual medley, while Australia’s Mack Horton took down Sun Yang of China without giving his bitter rival so much as a passing glance.

The bad blood between the two was on display for all to see as Horton celebrated after the race without even acknowledging the runner-up. Sun made a move as though he wanted to congratulate Horton, but the winner looked the other way.

Horton’s winning time was 3-41.55, just 13-hundredths of a second ahead of Sun. Italy’s Gabriele Detti rallied past American Conor Dwyer, the top qualifier in the prelims, to take the bronze in 3-43.49.

Australia broke its own world record on the way to claiming gold in the women's 4x100 metre freestyle relay final.

The quartet - consisting of Emma McKeon, Brittany Elmslie, Bronte Campbell and Cate Campbell - touched the wall in three minutes and 30.65 seconds, three tenths quicker than their previous marker set in 2014.

Australia trailed the United States in the early stages but had moved into the lead by the 300m mark and held on for the country's second gold in the pool, with Mack Horton having triumphed in the men's 400m freestyle earlier on.

The American team came home in second, finishing a second clear of Canada, which took the bronze medal.