Jorge Sampaoli is searching for certainty in Argentina's team selection ahead of the World Cup, as the beaten 2014 finalists prepare to face Spain in Madrid.

La Albiceleste defeated Italy, who failed to qualify for the finals in Russia, 2-0 in Manchester on Friday, although they were without key player Lionel Messi due to a minor injury.

Questioned on his team's approach to the impending meeting with Julen Lopetegui's side at the Wanda Metropolitano, home of Atletico Madrid, Sampaoli said: "We'll face it with the same focus that [we had for] this match. 

"We'll try to maintain the idea we used today, regarding each opponents' characteristics, knowing we have to improve some things we did today, trying to generate more domination [in the opponents' half of the] field, we are on that path. 

"Spain already has its team and knows how it will play at the World Cup, we have to find that certainty.

"We came to these friendlies looking for that. I leave really calm after seeing what we talked [about] before the match and what the players did on the field, more than for the result itself, and we'll look [for] the same against Spain."

In the absence of Messi, Sampaoli opted to use the less storied figure of Paris Saint-Germain's Giovani Lo Celso as a playmaker behind striker Gonzalo Higuain, flanked by Angel Di Maria and Manuel Lanzini. 

"On the last day [of training] we made the game plan with Leo but unfortunately that injury appeared and we decided to not include him," Sampaoli said of his tactics. 

"So we decided [to go] with Gio, who had trained with the other group, to take Leo's position so we didn't have to modify our plan, and beyond the individual level, we had some players with good development during the game, they respected the idea a lot.

"We had the idea to play as [if it was] the semi-finals of the World Cup, knowing we had a very tough opponent before the game and that we had to work it out, with a very clear idea, and there were some links on the field that allowed us to grow."

Argentina will face Iceland, Croatia and Nigeria in Group D at the World Cup.