Barbara Bonansea fired Italy to a remarkable comeback win over Australia after her brace, including a stoppage time winner, claimed a 2-1 Group C victory on Sunday.
Juventus' Bonansea pounced on a dreadful first touch from Clare Polkinghorne to race through and level for the Italians 11 minutes after the break after hotshot striker Sam Kerr had rammed home the opener for the Matildas on the rebound from her own 22nd-minute penalty.
Daniela Sabatino thought she had won it for Italy with nine minutes remaining when she finished well after hitting the post, only for her goal to be ruled out for offside.
But Bonansea scored from a free-kick five minutes into added time to see the Italians home on their return to the World Cup after a 20-year absence.
The three points puts Italy at the top of the group ahead of Brazil's clash with Jamaica later on Sunday.
England also open their World Cup campaign with a Group D derby against Scotland in the day's late game.