#1 Keep Messi away from the midfield

Messi is the sole reason why Argentina creaked into the World Cup finals and he will play a big part in determining how far the team will go.
The problem with being Messi however is that every team prepares detailed plans to contain him and when these plans work out, Argentina’s attack usually suffers for it.
The Icelandic midfield and defence did a great job of marking and anticipating his every move as whenever he got the ball (or even when he wasn’t with the ball), there was always an Icelandic player dogging his heels and giving him no breathing space or time to work his magic.
He wasn’t helped by the poor midfield deployed by Sampaoli. He dropped deep too often to get the ball and orchestrate attacks, a move which gave the Icelandic midfield/defence time to re-adjust and get into position.
Sampaoli will need to talk to his captain and get him to stay as close to the opposition’s 18-yard box as much as he can. This would ensure that the opposing defenses would be constantly pinned back, as they would be scared to commit too much for fear of leaving the La Pulga unmarked.
However, for this to work, the Albiceleste midfield would have to pass the ball quicker and transition faster. This is a job that only Banega and Lo Celso could do to a certain extent in the team, either or both of these players would have to be trusted with a starting berth.