The Ivorian has netted 12 goals in his debut season at the DW Stadium, including two in his last two games to help the Latics post consecutive victories over Newcastle and Norwich.
But Martinez believes the 29-year-old, who he described as "very important" to the club, will continue to get better towards the end of the season.
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“We’ve been very impressed at how he has settled in this league. For any striker that comes into the Premier League it takes time for them to get to know the physicality and tempo of the game, but right away he adapted really well.
“Although he is enjoying the best moments of his career, the best is still to come.”
Kone's impressive form this term has led to speculation over his future, but Martinez insists he is unconcerned by such talk.
He continued: “Over the years we’ve learned not to focus on trying to keep players.
“We’ve been focused on bringing players in who can perform well for Wigan Athletic, to allow them to enjoy their football, and be as good as they can be for the duration they are going to be here.
“Of course, we’ll never stop a player if they feel they have to move, but that will always be at the right price and the right time.“