Merino believes Spain must find a way to neutralise Lionel Messi’s influence if they are to lift the World Cup.
It is a huge challenge and an incredible motivation for me and the whole team,” Merino said.
“Playing against a team like Argentina, who are the defending champions, makes the match even more special. I am very happy to be part of this moment.”
The Arsenal midfielder has been one of Spain’s key players despite often starting on the bench. He scored dramatic late winners against Portugal in the last 16 and Belgium in the quarter-finals to help send Spain into the final.
Merino said he is always confident he can make a difference when called upon.
“I have great confidence in myself and in my abilities. Every time I go onto the pitch I believe I can help the team,” he said.
“But it does not matter who the hero is. The important thing is that the team wins. When you win a title, it belongs to everyone, not only the starting eleven.”
Merino also praised teenage winger Lamine Yamal, describing the 19-year-old as an “impressive” talent ahead of his first meeting with Messi in what many see as a clash between Barcelona’s past and future.
The 30-year-old expects a fiercely contested final and believes match officials will have an important role to play.
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“It will be an intense match,” he said. “The referee will need to control the intensity and the number of challenges and fouls. The quicker we move the ball, the less opportunity the opposition will have to stop us with fouls.”
Spain are aiming to lift the World Cup for the second time after their historic triumph in 2010. Although Merino admits he has only limited memories of that success, he understands what wearing the national shirt means.
“Representing our country and inspiring the next generation of children watching us is something magical,” he said.