Heading into this game on the back of victories over the United States and Ireland Wolfhounds, the Scots went in at half-time 8-0 up thanks to Ryan Grant's early try and a David Blair penalty.
Another Blair penalty after the break stretched the hosts' lead, before Tito Tibaldi finally got the Italians on the scoreboard with a penalty of his own.
In a constant downpour, the home side kept the Italians inside their own 22 for the first 10 minutes and, when skipper Antonio Pavanello was sin-binned, quick thinking by Greig Laidlaw put prop Grant over for the try.
Blair missed a difficult conversion into the wind but made amends with a 17th-minute penalty.
The Italians then started to come into the game, with flanker Luca Petillo with lock Josh Furno influential, but the Scotland defence held firm.
A string of missed penalties by Riccardo Bocchino did nothing for Italian morale and the Scots went in at the interval 8-0 ahead.
The rain continued to lash down throughout the second half but, despite horrendous underfoot conditions, Scotland managed to stretch their lead. A Simon Danielli kick gave them the field position and, when the penalty was awarded, Blair delivered.
The Scots then had to withstand a huge spell of Italian pressure with veteran Marco Bortolami and Pavanello both coming close but, after 20 minutes inside the Scotland half, they came away with only a Tibaldi penalty.
The home side looked to turn the screw in the closing stages but the Italy defence stayed solid to keep the scoreline respectable.