irb.com and James Mortimer 13.Oct.2013Getty Images
Sir Gordon Tietjens' side beat USA (38-0), Tonga (26-0) and Kenya (31-0) and will now face Samoa in the Cup quarter finals on day two.
South Africa were the only other side to maintain a 100% record and they will play Wales, while Fiji and Ben Ryan will come face-to-face with England.
The hosts Australia bounced back from a 21-21 draw with Scotland, a match in which they led 21-0, to win their matches with Argentina and Samoa to the delight of the home crowd.
They will now play Kenya in the quarter finals after they beat Tonga and USA in their first two matches before coming up against the reigning Series champions.
Sean McMahon scored Australia's first try of their home tournament, but they were pegged back to 21-21 when James Fleming scored with the last play of the match.
In their second match, Nick Malouf scored two tries in a 22-7 win over Los Pumas before some excellent defending ensured they beat Samoa 12-0 in the final match of the day thanks to tries from captain Ed Jenkins and Shannon Walker, and some excellent defence.
Defending champions Fiji lost to Wales 22-19 in the penultimate match of the day but their points difference was enough for them to top the pool, while Simon Amor's England were defeated 22-14 by Neil Powell's South Africa in the Pool B decider.
On a day of mixed fortunes for the nine new coaches, while five are still in the hunt to lift the Cup, the other four will compete in the Bowl.
Matt Hawkins and Argentina's Santiago Gomez Cora both had to wait until the last set of matches for their first wins, and they came against Tonga and Scotland respectively with Scotland and Tonga awaiting them in the Bowl quarter finals.
Spain and Portugal are still looking for their first wins under their new coaches, and will meet Canada and Portugal on day two.
Earlier in the day, Dan Bibby scored the first hat-trick of the season, while Waisake Naholo scored the first try of the season against USA in the opening match of the day.