A triple treat from Willy Bishop has secured Australia a quarter-final berth at the Adelaide IRB Sevens tournament.

The former rugby league player marked his first starting appearance for the Australian Sevens with a brilliant three-try performance.

New Zealand-born Bishop, who has played league for the Sydney Roosters and Manly, helped Australia dismantle the United States 31-19 in a second round victory that ensured a berth in Sunday's quarters.

"He's got a wicked sidestep and he really led the way," Australian coach Bill Millard said of Bishop.

"With that sort of talent with his feet .... he has just got to get used to union and settle and he's going to be a great talent for us."

Earlier, the host nation relied on a last minute try from James Lew to eclipse Canada 21-14 in their opening match of the Adelaide Oval tournament.

The triumphs booked a passage into the quarter-finals regardless of the result of Australia's final round match, against South Africa.

Also through to the quarter-finals with consecutive victories was tournament favourite New Zealand, who dispatched Argentina 21-14 and the Cook Islands 31-7.

That stretched their extraordinary unbeaten run in Sevens to 44 games and a tournament victory on Sunday will give the peerless New Zealanders eight world Sevens title in the past nine years.

Fiji, Kenya, Samoa, Tonga and South Africa also all advanced to the quarter-finals, the Fijians shrugging off a match-fixing controversy to record convincing wins against England and France.

Fijian coach Josateki Savou has alleged former star player and coach Waisale Serevi, considered the best Sevens player in the world, influenced players to perform poorly in last weekend's Hong Kong Sevens tournament.

Serevi denied the allegations that were being investigated by members of the Fiji Rugby Union board in Adelaide.

The last Sevens quarter-final berth will be decided on Saturday night, with Scotland and Argentina vying for the honour.

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