A resilient Italy side made it four wins from as games played after defeating Portugal in Estoril courtesy of a solitary goal chalked up by Daniela Sabatino late in the first half.
However, it took a collective effort to snatch the three points against a side which left a good impression of itself in last summer's UEFA Women's Euro 2017.
Milena Bertolini's team are now the new pace setters in the group with 12 points, three ahead of Belgium who however have a game in hand.
Portugal, on their part, see their chances of qualifying to France 2019 diminish as their gap from Italy has now extended to nine points.
Italy's defensive prowess
Bertolini deployed a 4-4-2 flat with skipper Sara Gama covering the right back role instead of her usual central position.
In the midfield area, Martina Rosucci was entrusted with the holding midfielder task while upfront Italy threatened with their duo Barbara Bonansea and Ilaria Mauro.
The hosts went all guns blazing from the early stages with Carolina Mendes threatening first.
However, Italy started to inch up their way on the field and on the half-hour mark Bonansea hit a sublime shot just to be deflected into corner.
Nonetheless, the goal it was a matter of time when seven minutes later, the Juventus winger dazzled past two opponents before letting fly an inviting ball into the box on which Sabatino connected to draw first blood.
Vanessa Marques went close to restore parity on the brink of half-time but she could not direct the ball into the net.
After the change of ends, Portugal squandered a golden opportunity through Diana Silva with the scoreline still putting Italy ahead.
The game went from end-to-end action with Sabatino being the main threat for Italy.
The home crowd was held on its edge for much of the game as both teams gave the impression they could notch a goal from one moment to another.
In the latter stages of the game, Portugal seemed to have snatched a dramatic point only for the referee to disallow the goal due to a foul on Italy's goalkeeper.
Group leaders Italy will take on Moldova on April 6 while four days later they will cross swords with second place Belgium, with the Azzurre hosting the first tie.
GROUP 6 - Results and standings as of November 28
- Romania vs Moldova 3-1
- Portugal vs Italy 0-1
Standings: Italy 12 points; Belgium 9; Portugal, Romania 3; Moldova 0.