Argentina's tactics: Messi and 10 more

In Argentina, much speculation is on how best to utilise their attacking options against Spain on Tuesday, and, above all, during the World Cup in Russia.

In an overview of their training session on Sunday, the camaras captured Sampaoli's notebook containing notes on his different team selections heading into the friendly in Madrid.

Among the usual variety of options, one thing stood out: the use of Lionel Messi as a wildcard, making it clear what everyone had already suspected, that Argentina will play their magician alongside ten others.

Marcos Rojo and Nicolas Otamendi were one of Sampaoli's defensive partnership, as well as Federico Fazio and Ramiro Funes Mori.

In the core of midfield, Javier Mascherano and Ever Banega face competition from Lucas Biglia and Pablo Pérez whilst Fabricio Bustos and Nicolás Tagliafico make up the positions on the wing.

Up front is where things get a little more complicated, Sampaoli must choose between Gonzalo Higuain, Cristian Pavón, Maximiliano Meza, Diego Perotti and Lautaro Martínez to partner Messi.

It's two very different systems in which Messi could play either behind in an attacking three or just off to the left, like he does for Barcelona.

Both seem like formations in which Sampaoli is trying out to see which one accommodates his captain better, ready for Russia in the summer.