Barbara Bonansea stunned Australia with a last-gasp winner as Italy took a surprise 2-1 victory in Valenciennes.
The Juventus striker netted her second goal of the game in the fifth minute of stoppage time to give Italy an ideal start to their Women's World Cup campaign Sunday.
Captain and star striker Sam Kerr opened her tournament account for Australia, the world's sixth-ranked side, but the Matildas lost their way in the second half and were punished.
Kerr missed a golden chance in the third minute of the opening Group C match when she headed over from Steph Catley's terrific left-wing cross, before a VAR referral saw Italy denied an opener.
Bonansea raced through from close to the halfway line and bundled the ball past Lydia Williams, but an offside verdict that took over two minutes to be resolved went Australia's way.
Australia, quarterfinalists at the last three World Cups, was handed a penalty in the 21st minute when Kerr was tugged to the ground by Sara Gama.
Laura Giuliani saved Kerr's kick, but the ball ran loose, and the Perth Glory striker swept home from close range.
Chloe Logarzo twice almost headed in as Australia pushed for a second goal, but underdog Italy leveled in the 56th minute when Bonansea pounced as defender Clare Polkinghorne carelessly let the ball run under her feet and into the path of the striker.
Bonansea raced through to slide into the bottom right corner, and teammate Daniela Sabatino had a goal ruled out for offside as momentum swung firmly Italy's way.
The winner came when Valentina Cernoia swung across a free-kick from the right in the fifth minute of stoppage time and Bonansea beat the Australia backline to the ball, heading into the left corner to spark ecstatic Italian celebrations.
94:39 - Barbara Bonansea's match-winning goal for Italy against Australia was timed at 94:39 & was the latest winning goal scored in normal time of a FIFA Women's World Cup match in the history of the competition. Drama. #FIFAWWC19 pic.twitter.com/5sGbuWRmvu
— OptaJoe (@OptaJoe) June 9, 2019