ROSARIO, Argentina — Ask a soccer fan to name the fiercest rivalry in Argentina, and it is a near certainty the reply will be Boca Juniors versus River Plate, the battle for Buenos Aires popularly known as el superclásico. Another capital derby, Independiente versus Racing, ignites the industrial suburb of Avellaneda, where those clubs’ stadiums are separated by a single city block.

But in this port city along the Paraná River, the hometown of Lionel Messi and the departure point for most of Argentina’s vast soybean exports, soccer breeds a division that is apparent on almost every street corner. At each turn in the city’s north side, walls, streetlights and sidewalks are painted the blue and yellow of Rosario Central. In the south, they are the black and red of Newell’s Old Boys. Murals, many of which stretch half a block, mark the teams’ territory.

There are no neutrals in Rosario.

“You’re either a Central fan, a Newell’s fan, or you’re nothing,” said Juan Yacob, who runs a Central-themed restaurant.

In the weeks before the teams meet, as they will Sunday after a rare lull in their century-old rivalry, the winds of unease blow strongest.