Australia crashed through the tiny Pacific island nation of Niue on the opening night of the Adelaide Sevens, notching a 40-5 victory after a pair of upsets befell England and Fiji.

The home side are ambitious about lifting the tournament trophy on Sunday at Adelaide Oval and made an ideal start, running in six tries to one, with 17-year-old back Liam Gill particularly impressive.

It is a big tournament for several members of the young Australian squad, as Wallabies coach Robbie Deans has taken a keen interest in their fortunes as he looks at the fast-paced format as a pointer to future 15s squads.

The Australians can rise to fourth on the world sevens table this tournament, a goal that was helped by the USA's upset win over England 24-21.

Pacific powerhouse Fiji, meanwhile, fell short of a sprightly Welsh unit that recorded an entertaining 17-12 result.

In the other matches, New Zealand brushed Scotland aside 31-0 and Argentina came from behind to claim a narrow 19-17 win over Tonga.

South Africa's first-up 40-0 win over Japan was soured by a knee injury to Steven Hunt, who doubled over in pain inside a minute of the kick-off and was later seen lumbering around on crutches.

Samoa, champions in the previous event in Las Vegas, emerged from a willing contest with France to win 33-12 in the tournament opener.

The Australians rested their captain Patrick McCutcheon from the match, and coach Michael O'Connor said he was quietly satisfied with the start in front of a crowd of around 6,500.

"Patty was on the bench so he'll be fresh for tomorrow, I was very happy overall, a very sound performance, but I think we can improve on it," he said.

"I think for and against-wise it was a good start for us given that the USA had a bit of a surprise victory over England.

"We were great at the re-start, that gave us a bit of possession, we were able to retain a bit of possession and when you've got possession in this game it's a big benefit."

Australia's remaining pool matches, against the USA and England, take place late on Saturday afternoon.

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