Despite heading into the tournament as one of the favourites, Reus believes that the main challenge for Germany will be to remain focused throughout their campaign.
"It is a World Cup, so the world's best teams are competing," the Borussia Dortmund attacking midfielder told Goal.com.
"It is going to be really tough, as many teams are trying to win and so are we. I think we have a great team this year but it remains a hard task.
"We need to be really focused, especially on the match days."
Reus has played 19 times for Germany, scoring on seven occasions in the process.