Zola bought in three strikers during the January transfer window with only one - Ilan - scoring.
But he insisted: "I feel Benni McCarthy was unlucky to pick up an injury as soon as he came and after that he lost 40 days. Since then, he hasn't been able to come back to his own standards.
"Mido has worked very hard for the team. Maybe he hasn't been very effective at scoring goals but he does well for the team. He didn't score against Everton but he really worked his socks off and that was important.
"It's not obviously the Mido that everyone remembers but there's still five games to go and he can still provide us with a goal to make a difference for us and that's what I'm looking for.
"I'm not going to waste time, sitting here, blaming him for anything. He's here, there are five games to go and maybe in that time he can score the goal that decides our season.
"Ilan is quiet but he has already given us something and I'm sure he can give us even more. He's a player with potential and sometimes - more than the others - he has to realise that he has to adapt to English football.
"He has to realise that it's a very physical game and adapt to that. But he has qualities and I'm sure that he will give us something extra."