São Paulo arrives at the Sudamericana quarterfinals unbeaten, with a back three and Dorival sold on his system

Eight games without a loss, a single goal conceded in the group stage, and a back three that started giving the team a whole new look. That is the quick summary of São Paulo, Boca's next opponent in the Copa Sudamericana quarterfinals. They do not arrive as a simple formality: they come in unbeaten, well organized, and with Dorival Júnior convinced he has found a shape that works for his team.

The Tricolor finished first in Group C with three wins and three draws, then eliminated Bolívar with a 4-2 aggregate score. Along the way, they conceded just one goal across the six group stage matchdays. And before traveling to Buenos Aires, they didn't rout anyone, but they did make a statement: a 2-0 win over Atlético Mineiro in the Brasileirao, a match Dorival himself singled out to praise his group.

Our best match, not because of the result, but because of our attitude.Dorival Júnior

The back three that changed the way the team reads the game

The first question for Boca centers on the formation. Dorival has been sticking with a back three, lately made up of Arboleda, Domingos Duarte, and Sabino, and the results have given him no reason to change it. It is not a shape designed just to shut things down defensively: with three men at the back, the team can push its wing backs forward, control the width of the field, and press higher up the pitch than usual.

That is the key to understanding this São Paulo side. With the ball, the wing backs push up and become almost like wingers. Without it, they drop back to form a line of five. That back and forth lets the midfielders tuck inside and gives the forwards more freedom to move between the lines, looking for the spaces the team's own structure opens up.

Luciano, Calleri, and Artur: three different ways to hurt you

Up front, the name to know is Luciano, the team's top scorer in this Sudamericana with three goals, including the opener in the second leg against Bolívar. He is not a fixed forward: he drops back, moves between the midfielders and the opposing center backs, and pops up in different lanes to link play.

Jonathan Calleri, a former Boca player, offers something different: a more direct point of reference, someone who can hold up the ball against center backs and play with his back to goal. He converted a penalty for the second goal in the second leg against Bolívar, after the Bolivian side had briefly leveled the score, and he arrives at this tie freshly recovered from an ankle injury that Dorival handled carefully. If he manages to occupy Boca's defenders, he opens up space for Luciano; if he drops in to combine, he can drag defenders out of position and open up room elsewhere.

The third name to watch is Artur, a left footed winger who operates on both flanks and fits perfectly with Dorival's idea: while the wing backs provide width, he can tuck inside and combine with Luciano and Calleri. In the group stage he already made his mark with two goals, including an assist against O'Higgins.

What Boca can exploit

São Paulo's continental campaign, unbeaten from the start of the group stage through the elimination of Bolívar, carries more weight as a point of reference than their inconsistency in the domestic league. There they have found the steadiness they still haven't managed to sustain in the Brasileirao.

But the system also has its cracks. If the wing backs get too eager and push too far forward, the flanks are left exposed behind them. And if the three center backs are forced out of position to cover Boca's forwards, the space in front of the back line can open up. That is likely where Arruabarrena will be looking to find a way to end an unbeaten run that now stands at eight games.