Germany were pegged back at 1-1 in the first half, but went in 3-1 up at the break and a rampant second period saw them coast to victory and sound a warning to their rivals at the global finals.
"It was a great start to the game, the first 15 minutes were fantastic," Nagelsmann said. "We had many attempts. The equalising goal from Curacao was unexpected, but it was fascinating to see how the team reacted to it.
"Curacao played better than many people in Germany expected, and they played differently than they had before and with courage. It is not easy to score seven goals, so we are quite satisfied.
"We are on the right path but there are things we can do better and we will have tougher opponents in the tournament."
Nagelsmann said his side had to be patient in the first half, but the intensity they showed in the second is what they will need if they are to add to their four World Cup titles.
"One team (Germany) has very high expectations and one (Curacao) doesn’t and that is tricky. At 1-1 we had to be patient, and the team really wants to give 100%. We played with the right intensity. If we do that we can have a good tournament," he said.
"We really needed this convincing win, and the confidence it will give us. That confidence was always there, but it has grown. It was important to show the people in Germany that we can perform.
"After the game, there was a song (from the German fans) called ‘the train has no brakes’. We will try to do that, to keep going and going in this tournament."
Germany face the Ivory Coast in Toronto on Saturday.
The 2026 World Cup will be held from June 11th to July 19th in the United States, Canada and Mexico. The tournament will feature 48 national teams and will be played in 16 modern stadiums.
Match schedule and times | Group tables | Full squads for World Cup | How to watch the World Cup