During the War of the Fifth Coalition, Bertoletti served in the Italian theater under the command of Eugène de Beauharnais, the Viceroy of Italy.

[4] In June 1813, Bertoletti defended Tarragona with 1,600 soldiers against British Lieutenant-General John Murray's 16,000-man army.

Realizing he could not hope to hold the outer walls with his small Franco-Italian garrison, he pulled back into the inner defenses and two outworks.

Ultimately, Murray abandoned the siege and 18 heavy cannon when he heard that two French relief columns were due to arrive.

When Murray's troops withdrew, Bertoletti alertly called for help from the nearest French column, which soon marched into the fortress.