Hungary's Katinka Hosszu filled a glaring gap in her resume Saturday, making her first Olympic medal a gold -- with a world record to boot.

Hungary's "Iron Lady" shattered the world record in the 400m individual medley, seizing control from the start and winning in 4min 26.36sec.

She eclipsed the previous record of 4:28.43 set by China's Ye Shiwen in London four years ago -- where Hosszu was relegated to fourth.

"Coming to Rio, I wanted to do the best I can and I did," said the five-time world champion. "In London, I was under pressure, I was nervous before the final, I was preoccupied by the idea of what would happen if I don't win.

"And I did not want to live through this again here in Rio," added the 27-year-old, who built her confidence up by swimming the second-fastest time ever in the heats.

"I was confident," she said. "Today, I had a great time swimming this 400 IM.

"I know I can go faster, going faster is what brings excitement for me."