malbec said:
Where are they playing? At River or at the chiquero?
In any case you would like to buy a platea ticket
YES, do NOT go to the popular (terrace, or as they say in North America the endzone) unless you are experienced here or going with someone who is. Otherwise, pay the extra for a platea (grandstand) ticket.
I often

go to the populares in Mendoza, and often in Cordoba and BA, and have not had problems; but have received accounts of and actually seen problems, including violent robberies of gringos. Do not take cameras or try to stand out as foreigners if you go to the populares. The thieves can smell you out like sharks can smell blood. And, remember that the police do not go into the populares, because they are afraid.
Suerte, and enjoy the great experience that only an Argentinean football match can give you!