New Zealand's clumsy effort in the field opened the door for Australia to claim first blood in the one-day series, in-form opener Martin Guptill says.
Loose bowling, spilled chances and imprecise use of their reviews helped the hosts reach 325 at the SCG on Sunday, leaving the Black Caps with a tall order.
Guptill's masterful 114 off 102 balls kept the game in the balance until his dismissal in the 33rd over, triggering a slump to 256 all out.
Australia wouldn't have envisaged a 68-run win when they were reduced to 92-4 but New Zealand's profligacy in the field helped them clamber back.
Captain Steve Smith dominated the recovery with a ground ODI record 164, supported by Travis Head (52) and Matthew Wade (38).
"We probably didn't bowl as well as we could have in the middle stages and at the end," Guptill said.
"It is a bit disappointing.
"We know we're better than that. We're going do our best in a couple of days if we have them in that situation again to really put the foot down."
Despite satisfaction at reaching an 11th ODI century, Guptill was disappointed not to complete the job. None of his teammates passed 50.
Guptill will be a key wicket for game two of the three-match series at Canberra's Manuka Oval on Tuesday.
Dropped from the Test squad following the tour of India, the free-hitting opener has scored tons in his last three innings.
He reached 128 not out and 151 in the Plunket Shield for Auckland.
New Zealand may consider changes, particularly to their bowling line-up after experienced seamer Tim Southee and legspinner Todd Astle were omitted.
Matt Henry (2-74) and debutant Lockie Ferguson (1-73) got Australian openers Aaron Finch and David Warner respectively to play on, but both proved expensive.
Ferguson generated good pace but was guilty of four no-balls in his nine overs.