Martinez said Midfielder Barkley's biggest weakness remains his decision making - too often the
young Everton star chooses the wrong pass.
But Martinez is impressed by the way the 21-year-old never hides following a mistake and says this shows his strength of character.
"He's a player who will maybe lose the ball three times, and he'll want it again," said
the Toffees' boss. "That's a sign of a player who'll find a way.
"He's got a top personality. You get a player who loses the ball a couple of times and they hide. That's when you've got a real issue.
"When you lose the ball three times and then want to hide, that's when you've got a problem. With Ross on the fourth time, he'll go past three players and give you an assist or a goal.
"That's the great thing about Ross, that personality. He doesn't need to be having a great game to give you something, and I will never have a problem with someone like that.
"You can't measure Ross on making one or two bad decisions. You can measure him on what he's doing every day on the pitch. I find it a period of his career that excites me because he never hides from the responsibility.
"He makes mistakes, but he never hides. The problem is when someone makes mistakes and starts hiding and doesn't want to fight for the team."
Martinez claims Barkley,
who he has tipped to become England's best player EVER, is finding it harder this season because he is a marked man and says
the Goodison club must utilise the space his opponents are creating to shadow him.
"I'm not concerned about him getting that attention," said the Spaniard. "I'm concerned with what we do with the extra space that should be created when he is marked by two men.
"It's a bit of a learning curve for us as a team how to utilise that and for him because I have been playing him in different positions, bombarding him with information to grow quickly, but I'm delighted with his performances."