Reigning Olympic champions the United States have been dumped out of the men's beach volleyball tournament by Italy in a major upset.

Todd Rogers and Phil Dalhausser, gold medal winners in Beijing, were soundly beaten in the last 16 by Italian duo Paolo Nicolai and Daniele Lupo.

Italy had only made the knockout stage by winning a 'lucky loser' playoff against Canada, but produced an inspired performance to beat their American opponents in straight sets 21-17, 21-19.

Nicolai and Lupo are the youngest team in the beach volleyball competition, aged just 21 and 23 respectively.

The Italians' appearance in the quarter-finals ranks as one of the biggest upsets in the history of Olympic beach volleyball.