Australia’s Ariarne Titmus wins gold in 400m freestyle at Tokyo Olympics

In a moment that will go down in Australian sporting history, Ariarne Titmus has won her first Olympic gold medal at her maiden Games, defeating five-time Olympic gold medalist American Katie Ledecky.

Australia's Ariarne Titmus after beating US' Katy Ledecky in the women's 400m freestyle final. Source: AAP

Australian swimmer Ariarne Titmus has won the gold medal in the women's 400m freestyle at the Tokyo Olympics.

The 20-year-old triumphed at her first Olympic Games in a titanic swimming final on Monday, defeating the United States' five-time Olympic champion Katie Ledecky.

Titmus' achievement is Australia's second gold medal of the Tokyo Games, following the women's 4x100m freestyle relay success.