The Spaniard is encouraged to see his prodigious young talent is already displaying experience well beyond his years.
"The goal that he scored was a wonderful piece of skill and a wonderful piece of quality but I was really happy with his contribution, the responsibility he took and his performance," Martinez told evertonfc.com. "Any youngster could be very, very proud of what he did. He got on the ball and he made us play.
"It's not about him wanting to perform like that consistently - I think that's where he is now.
"I think he is a lot older in terms of football experiences and I think his time with England has really helped him in terms of opening his mind.
"His loan periods have helped as well and going through a serious injury at a young age too [Barkley fractured his leg in three places while playing for England Under-19s in October 2010].
"So I would say he is a lot 'older' than his age reflects. All I am guided by is his work and what he has done in pre-season and, for me, he's a player in a very, very good moment of form but physically and mentally he's in a very good moment as well."
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