Mazzarri took the reins at Inter in May, charged with improving the club's on-field fortunes after a disappointing ninth-placed finish under Andrea Stramaccioni last season.
After a promising start to the campaign, Inter soon lost touch with the leaders and now face a battle to secure qualification for the UEFA Europa League.
A four-match winless run - including three straight draws against teams in the bottom half of the table - has left Inter hanging on to fifth spot in Serie A.
However, Mazzarri feels his side have deserved more and remains confident Inter will eventually be back among Serie A's leading teams.
"It's (been) an unusual year," he said ahead of Sunday's trip to Sampdoria. "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."
With Juan Jesus set for a long lay-off due to a serious knee injury, Danilo D'Ambrosio is set for an extended run at full-back.
The 25-year-old moved to San Siro in January from Torino, and Mazzarri believes he will continue to improve.
He added: "D'Ambrosio is in the process of adapting. He's taken a step up by joining a club where you have to live with pressure.
"I'm sure D'Ambrosio has a great future, he's another one who's improving in leaps and bounds."
