Dania rider Iversen showed tremendous bike control to push ahead of Britain's Tai Woffinden (Wielka Brytania), who had put in a superb showing to get to the final race in Terenzano.
Emil Sayfutdinov came third and remains top of the 2013 SGP standings with 107 points to Woffinden's 102.
Matej Zagar also reached the Italian final and ultimately came in fourth position .
Peterborough host second-place Wolverhampton in must-see clash
Russia's Sayfutdinov and Woffinden are some way ahead of the rest of the pack in the overall, with Jaraslow Hampel in third on 85 points.
Wolverhampton and Sheffield set for second Speedway tie in five days
Belle Vue travel to Wolverhampton looking to spoil Schlein's swan song season