Morecambe fielded three centre-backs in a bid to counter Vale's firepower and the plan worked well to frustrate the home side in an uneventful start.
The first effort of note was a shot from visiting wing-back Andrew Wright which warmed the fingers of Vale keeper Chris Neal in the 22nd minute.
But that was a rare moment of excitement in an unproductive first-half in which Vale battered at the Morecambe door without forcing Barry Roche into a serious save.
Vale attempted to up the ante at the start of the second-half with Doug Loft and Tom Pope off target with half chances as the visitors continued to sit deep.
But Morecambe did start to show more adventure and Kevin Ellison fluffed a good chance before the all important goal arrived in the 63rd minute.
The Vale defence failed to deal with Gary McDonald's cross from the left byline and Alessandra tapped in the loose ball at the far post.
McDonald then showed his defensive prowess when he cleared Darren Purse's powerful header off the line two minutes later and Vale's pressure intensified after Morecambe were reduced to 10 men 18 minutes from time.
Wright was sent off for a second yellow card following a foul on Ashley Vincent, but Jim Bentley's team, with Roche performing heroics, were not to be denied as they held on for their fourth win in five games.