However, the Barcelona forward saw his effort smartly saved by Iceland goalkeeper Hannes Halldorsson, which culminated in a share of the spoils come the final whistle in Moscow.
"We tried to work better and create more opportunities, but what can you do? We're just starting," Sampaoli told reporters at full time. "We will learn from this experience.
"Beyond the goal scored against us, I don't think our transitions were fast enough and we should have hurt our opponent more. In the second half we made them feel uncomfortable but they did have many people playing defensively.
"We need to find more alternatives to our style of play - alternatives that can hurt our opponent. Croatia is not the same as Nigeria or Iceland. The next game will be different and we must understand what strategy works best. This is going to be a tough group."
Argentina return to action on Thursday night against Croatia in Nizhny Novgorod.