The 30-year old Omani international has been a consistent performer for the Latics since his move from Bolton following a 2010 loan and despite his horror mistake in the 3-2 win over Reading on the weekend, Martinez admits it would be extremely difficult to replace such a player.
"I wouldn't take any other keeper to replace Ali and that's how much we rate him," the Spaniard told reporters.
"He's the perfect goalkeeper for ourselves. He's someone who can fit in with the way we want to play. He's someone who's still developing and in every aspect is the perfect goalkeeper for Wigan Athletic.
"This won't affect his ¬confidence. If anything, he's a more focused character now. He will want to be perfect, he will get better.
"I'm quite happy for him to make a mistake - for every mistake, there are 20 good saves. I'll take that ratio any time."