Expect Leganés to line up in their usual 4-4-2. It's a shape built on structure and discipline — two banks of four, narrow when defending, quick to release the wide men on the break. The double pivot in midfield will look to control the tempo, and the two strikers will feed off scraps and second balls. At home, they'll push higher and look to pin Alcorcón back. The full-backs will get forward, but the real threat comes from the wide midfielders cutting inside onto their stronger feet.

Alcorcón will likely set up in a 4-2-3-1, a shape designed to frustrate and then strike on the counter. The two holding midfielders will sit deep, screening the back four, while the attacking midfielder tries to find pockets between the lines. They'll look to hit on the break, using the pace of their wide players. But here's the thing: when you're a division lower and you come to a place like Butarque, the temptation is to park the bus. That's a dangerous game against a side that's used to breaking down low blocks. Leganés have the patience and the quality to wear them down.

The key battle will be in midfield. Leganés' 4-4-2 gives them numerical superiority in central areas, and if they can win that dogfight, they'll starve Alcorcón of the ball. Set pieces could also be decisive — Leganés have the height and the delivery to cause problems from dead balls. Alcorcón will need to be perfect defensively, and that's a big ask over 90 minutes.