The 52-year-old, who took charge at Inter in May, has overseen a four-match winless run, including three straight draws against teams in the bottom half of the table, which has left them hanging on to fifth spot in Serie A.
However, Mazzarri believes his side have deserved more and remains confident that the San Siro club will eventually be back among Serie A's top teams.
"It's [been] an unusual year," he is quoted as saying by Goal.com. "There haven't been many games that we didn't deserve to win.
"I've never seen the team really struggling. In fact, we've often picked up less than we deserved. We've often determined the course of games with the approach we've taken, that can be seen as a positive.
"I know we'll get back to being a competitive side with working methods that are different to the past. We've let teams peg us back after going ahead. That's the area where we need to make the biggest improvement."
Inter, who finished last season in ninth place under Andrea Stramaccioni, travel to fourth-placed Sampdoria tomorrow.