Montrose walked away with all three points at the Marbill Coaches Stadium this afternoon.
It was a tale of two penalties in the opening 20 minutes with Owen Stirton and Michael Ruth netting for either side.
Stirton netted his second on 24 minutes with Pignatiello bringing Dumbarton level before the break.
Aiden Quinn netted the winner for the visitors midway through the half, getting on the end of a deep cross to the back post.
Sons travel to Cove Rangers next weekend.