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."