The Croatians know fully well theyre up against one of the top teams of the tournament and would obviously prepare to meet them. I think Argentina would probably come out the victor but Ive been wrong on my predictions before 
Not only you, all of us have been wrong with our predictions on many occasions in this world cup 
, and it is because the tournament is one of the best i have ever witnessed, so tough and hard to pick a winner, even if you pick one, the game may not go in the way of that team, making your prediction wrong. Croatia have a big chance to beat Argentina, the Argentine national team haven't been too strong, Messi is making most of the difference for them, but the squad doesn't have many players that are of great quality and they are surely beatable, Croatia are looking to make it back to back finals, and it is even possible for us to see a repeat of 2018 final this year, this world cup is a wonderful tournament, i did not expect all these drama.