The Croatian striker has been resigned to a bench role recently due to the stellar form of Romelu Lukaku and Martinez has challenged the former Rangers ace to get back to the positive displays he showed when he first arrived at Goodison Park.
However, the Spaniard has been impressed by Jelavic's work ethic and hopes that remains.
"His attitude has been a 10 out of 10 and that's why when a player comes on as a sub he makes a big difference and the team benefits," he told the Liverpool Echo.
"It's a real focus to be as good as you can as an individual, but everything comes down to the team so Niki, Arouna (Kone), and everyone who isn't starting needs to do what they can to help the team.
"In a competition of 10 months you need everyone ready, everyone working hard, and whoever is on the pitch benefits from that. Nikica Jelavic has been really important in the way he works.
"I thought he worked really hard in his early performances and they were really good."
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