The Newcastle flier feared for his place in the Argentina team when the Toon were relegated last summer.
He said: "Diego's support was very important for me. The team had just gone down to the Championship and they didn't want to loan me out to anyone.
"I thought I'd have a real job making the squad but when I was called up for the friendly with Russia he told me not to worry.
"He said what mattered was how I was playing and not the league I was playing in. That really helped."