“When I got there I was actually enjoying it. I wasn’t anxious, I wasn’t nervous, I was full of confidence and saying ‘this is my time’.”
Martinez had made just 13 first-team appearances for the north London club before last season, when he appeared 23 times.
He had previously spent spells out on loan with Oxford United, Sheffield Wednesday, Rotherham United, Wolves, Getafe and Reading.
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The South American added ahead of his switch to Villa Park: “With my family we decided, after 11 years at the club, you work 10 years so hard, you will leave through the front door today.
“For me, I couldn’t be happier to leave through the front door with the Arsenal fanbase supporting me, the club.
“I’m just very grateful for the 11 years at Arsenal, even though it was a hard road for me and I suffered through my time at Arsenal.
“Today I’m happy and I try to show young goalies that hard work pays off. When you work hard, you’re not going to be happy the whole time, you’re going to have frustration, bad times in your life, but you have to work past that.
“When you work past that you will see the light, and that’s what I saw when I won the FA Cup and the Community Shield.