Australia's Horton upsets China's Sun to win men's 400m freestyle gold

Mack Horton of Australia and Sun Yang of China compete in the men's 400m freestyle final on Saturday.[Photo/Agencies]

RIO DE JANEIRO - Mack Horton clinched Australia's first gold medal of the Rio Olympics by upsetting favorite Sun Yang of China in the men's 400m freestyle final on Saturday.

Horton clocked 3 minutes 41.55 seconds, eclipsing Sun by just 13 hundredths of a second at the Olympic Aquatics stadium. Gabriele Detti of Italy was third in 3:43.49.

Mack, who finished second fastest in qualifying, is competing at his first Olympic Games in Rio. The 20-year-old was the bronze medalist in the 800m freestyle at last year's world championships in Kazan.

Sun was the pre-race favorite, having won gold in the same event at the London 2012 Games. The 24-year-old is also the defending 1500m Olympic champion.