Austria went on to face USA in the semi-finals, with the world champions having beaten Italy 33-12 in the quarters.
And the Americans had to fight back before clinching a thrilling 46-39 win at the death.
On the other side of the draw, Canada progressed to the semi-finals by beating Japan.
Mexico then secured a 25-13 win over Canada to set up a repeat of the 2022 final, when they shocked USA by winning 39-6 in Birmingham, Alabama.
Before Sunday’s final, Canada will face Austria for the bronze medal while GB play either Japan or China for fifth place.
Japan are ranked third in the world and beat Britain 40-34 in the quarter-finals of the Worlds, but GB managed to beat them 26-24 on Friday to finish runners-up in Group B with two wins from three games.
