The Croatia international is pleased with his progress in the past 12 months despite a frustrating start to the season - but believes his side should be challenging at the top
The 20-year-old has developed into an important first-team player at San Siro in the past few months after being largely restricted to a susbtitute role in the early part of the campaign.
Although he admits he found life tough at the start of 2013-14, Kovacic has credited Mazzarri for helping him to improve, particularly on the defensive side of his game.
"I've come on a lot tactically this year, I've got to know Italian football more and the coach has helped me improve defensively and add a bit of bite to my game," Kovacic was quoted as saying on the club's official website.
"It's definitely been a difficult year, because I wasn't playing a lot at the start. I've still learned a great deal, though."
Inter have struggled for consistency this season and sit fifth in Serie A heading into the final game of the season - a full 15 points behind Napoli in the final Champions League spot.
Although Kovacic acknowledges the improvement on last season's ninth-placed finish, he concedes a side of Inter's stature should at least be battling amongst the top three.
"It's been a tough year, but definitely better than the last. We've come fifth and we shouldn't be happy about that because Inter need to finish at least third," he added.
"We've played well in some games and less so in others. Now we need to focus on our last match against Chievo, then think about next season."