The Argentinean youngster found himself scrapping with home hero Andrea Mazzocchi on Saturday’s opening leg and trailed the 27-year-old by 7.5sec overnight.
Soria upped the tempo on Sunday morning, reducing that deficit to just five-tenths of a second after two stages. Mazzocchi then folded under the pressure and crashed out on the very next stage - leaving his rival clear at the top.
A clean run for Soria across the final loop saw him take the one-make Renault Clio Rally5 series spoils by 38.0sec from Giorgio Cogni.
He now leads the championship by 37 points from Sergio Fuentes - who finished third overall - with one round to go. Double points will be awarded at Barum Czech Rally Zlín (26 - 28 August), which means only 50 points remain up for grabs.