The Nerazzurri coach feels his side should have put the match against Torino to bed well before the final whistle.
Inter coach Walter Mazzarri has called for his side to develop a ruthless streak after Sunday's narrow 1-0 Serie A win over Torino at San Siro.
Rodrigo Palacio scored the only goal of the game in the first half as Inter strengthened its aspirations of securing European football next season, but Inter was stretched for periods after the break and was posed problems by the visitors' striking duo of Ciro Immobile and Alessio Cerci.
Torino's efforts eventually proved to no avail, but Mazzarri feels there are lessons to be learned from the Nerazzurri's win.
"We need to be more convincing and meaner, and never be satisfied with keeping it 1-0," Mazzarri told the official Inter website. "We did this in part, but at times we were missing a bit of luck with the final pass. We should have tried to close things down completely since one little mistake can cost you the three points.
"The only drawback today was not having shut down the game completely, as we saw at the end."
Inter sits fifth in the Serie A table at the moment with 44 points from 27 games.