Italy midfielder Giulia Dragoni become one of the youngest players to appear in a Women's World Cup match at the age of 16 years and 259 days as Le Azzurre scored late to beat Argentina.
Manager Milena Bertolini put her faith in the youngster who only made her debut for the senior side on 1 July.
It looked as though Italy were going to be frustrated by a gritty defensive performance by Argentina before substitute Cristiana Girelli, who replaced Dragoni in the 83rd minute, nodded the winner four minutes later.
The vastly experienced Girelli got on the end of Lisa Boattin's cross and looped a header 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.
A tetchy contest was stopped numerous times to allow players to have treatment, while Argentina's Mariana Larroquette, Miriam Mayorga and Florencia Bonsegundo were booked along with Italy's Caruso and captain Barbara Bonansea.
Italy, who also included 18-year-old forward Chiara Beccari from the start, go to Wellington next to play Sweden, who have a two-point lead at the top of Group G, on Saturday (kick-off 08:30 BST).
Argentina's next match is against South Africa in Dunedin on Friday (01:00 BST).