A nervous start and poor execution in extra-man at both ends of the pool have cost the Aussie Sharks in their opening game of the London Olympics going down to Italy 8-5 at the Olympic Water Polo Arena in London.

The world champion Italians were dominant in extra-man netting an incredible six from eight, including five from six in the opening half, to put a strangle hold on the Australians.

The Italians unleashed an array of extra-man moves early to dismantle the Sharks defence and lead 3-0 at quarter time.

Both Gavin Woods and Jamie Beadsworth were also able to create numerous kick outs at centre forward, but the Sharks' first quarter cohesion was lacking.

The Sharks responded in the second and third terms to reduce the margin to two with Western Australian Tim Cleland netting Australia's first goal for the Games and goalkeeper Joel Dennerley proving a wall in defence.

Australia had a chance to pull within one in the last period with Aidan Roach and Johnno Cotterill netting key goals, but ex-Australian and 2004 and 2008 Olympian Pietro Figlioli proved a pest against his old nation.

The Sharks had their chances to test the Italians but a superb game by Italian keeper Stefano Tempesti combined with their 20 per cent extra-man conversion rate and poor first quarter cost them dearly.

Coach John Fox was disappointed with the result and hinted at some early nerves as a possible reason.

"We gave them a three goal start and you can't give world champions three goal leads," Fox said.

"The rest of the game was even and if not we were ahead.

"Their defence is good and their keeper Tempesti is the best in the world and he showed why today.

"Hopefully the nerves are now out of the system."

Fox and the Sharks now have two days to regroup ahead of their second game against Kazakhstan at 23.00pm on Tuesday AEST.

Aussie Sharks

Joel Dennerley, Richie Campbell, Tim Cleland, Johnno Cotterill, Aaron Younger, Jamie Beadsworth, Aidan Roach, Sam McGregor (c), Thomas Whalan, Gavin Woods, Rhys Howden, Billy Miller, James Clark

Result: Australia 5 lost to Italy 8

Qtrs: 0-3, 2-2, 1-0, 2-3

X man for: 1 from 5 and 0 from 1 penalty

X man against: Italy scored 6 from 8

AUS Scorers: Tim Cleland, Richie Campbell, Rhys Howden, Aidan Roach, Johnno Cotterill