Queenslander Renee Taylor scrambled home the opener in the 13th minute before 25-year-old Doncaster product Padget, who has overcome a series of setbacks to finally make her Hockeyroos debut, added the second in the 42nd minute.
Padget was making her debut alongside fellow Victorian Sophie Taylor and Goulburn product Naomi Evans, while Steph Kershaw celebrated her 50th cap with a best afield display.
Hockeyroos coach Paul Gaudoin said: “I think it was a very even match. Both teams had many chances. Perhaps we were able to take our chances more than Japan.
“I think it was a very tough match. We were pleased with some parts of our game and our attacking game with the ball but we need to be better when we don’t have the ball.
“We hope to be better against Korea tomorrow in that area.”
Australia takes on Korea in their second game on Thursday from 5:30pm AEST
Japan had the first chance of the game with Hockeyroos goalkeeper Jocelyn Bartram thwarting Kana Nomura’s second minute drag flick from a penalty corner.
Rosie Malone came close with a reverse stick effort, before playing her part in the lead-up to set up Taylor’s opener.
Gold Coast’s Malone cut in on the baseline before squaring for Taylor whose initial effort was blocked by Japan keeper Akio Tanaka, before forcing home the rebound.
Savannah Fitzpatrick and Malone tested Tanaka again early in the second, while Japan rallied with some late chances in the opening half.
Tanaka was aware again to deny Fitzpatrick and Mikaela Patterson in the third period, before Padget capped off a fine move with Australia’s second.
Gerringong’s Grace Stewart did brilliantly to keep the ball in play on the left flank, passing for Lily Brazel who bounced past two defenders to cross for Padget to convert at the far post.
Japan continued to dominate the short corners’ count, with four in a row after the final change but Australia defended well to cap off a solid first-up win.
Australia 2 (Taylor 13’, Padget 42’)