Muller netted a hat-trick on Monday as the three-time champions got their campaign off to a dominant start.
Gotze believes that the forward's "decisive" presence on the pitch could help the Germans go far out in Brazil.
"Thomas Muller's performance was outstanding," he told FIFA.com. "There are certainly worse ways to begin a tournament. Now he's got three goals. That was very, very important, both for the team and for Thomas himself.
"He's clinical in front of goal and can score from nothing. The ability to do that, especially at a World Cup, can be decisive."
Germany are back in action on Saturday when they take on Ghana in Fortaleza.