Chances were few and far between during the opening stages, with only Inter's Rodrigo Palacio forcing a save out of either goalkeeper.
The home side, who won their first match in four last weekend against Cesena, kept up the pressure and Icardi was unlucky not to add his sixth of the season when his header was prevented from finding the top corner by Sergio Romero.
Back came Inter, who had Icardi bring another save out of Romero, but moments before half time, Sampdoria's Alfred Duncan struck the crossbar from 14 yards after being set up by Gabbiadini.
Despite the lack of goals, the game remained entertaining with Stefano Okaka and Gabbiadini having efforts saved moments after Palacio had narrowly missed the left post for Inter.
Zdravko Kuzmanovic responded positively for Inter but he too couldn't break the deadlock before Palacio broke clear of the Sampdoria defence but could only strike the ball past the left-hand post.
A point apiece would have been a fair result but after Romagnoli had hauled down Kuzmanovic, Icardi stepped up to send the ball into the right corner to earn his side their second win in a row.