"If he doesn't I will go to Rosario, to Funes (Messi's home town) to see if I can get Messi's autograph," said Merina.
Messi, 35, finally crowned his record-breaking career with football's biggest prize as he produced one of the greatest World Cup final performances, scoring a first-half penalty and netting again in extra time.
In doing so he emulated his predecessor as Argentina's idol, Diego Maradona who inspired the country to their second world title with a series of match-winning displays at Mexico 1986.
"I remember '86 but this victory yesterday was much more emotional and much more stressful," architect Ricardo Grunfeld, 65, told AFP.
"I don't know if there's any difference with '86 but this comes at a good time," added Zulema Guereri, 80.