Striker Cristiana Girelli came off the bench to head an 87th-minute winner as Italy won their Women's World Cup opener 1-0 against Argentina.
Girelli replaced midfielder Giulia Dragoni, who at the age of 16 years and 259 days became one of the youngest players in the tournament's history.
Azzurre manager Milena Bertolini put her faith in youngster Dragoni who only made her debut for the senior side on 1 July, but ultimately it was experienced Juventus player Girelli who made the difference.
It looked as though Italy were going to be frustrated by a gritty defensive performance by Argentina before substitute Girelli, who replaced Dragoni in the 83rd minute, nodded the winner.
The vastly experienced Girelli got on the end of Lisa Boattin's cross and looped the ball over Vanina Correa to secure a 1-0 victory.
In front of a crowd of 30,889 spectators, Italy had earlier seen goals by Arianna Caruso and Valentina Giacinti ruled out for offside.
