Maria recounted the dazzling 30-minute spell by which himself and his fellow coaches were convinced to sign up the teenager from Trapiche.
He told BBC Sport: "Roberto arrived for a trial in the middle of 2008.
"Generally trials last a maximum of one month, but depending on the player it can be less: two weeks, 10 days, etc.
"Roberto's trial lasted only 30 minutes - he was exceptional. He practically did nothing wrong, showed immense technical quality, and to top it off scored two bicycle kicks.
"Afterwards, everyone was talking about him and I realised we had a very special player on our hands."