Two goals from Robin van Persie and Arjen Robben condemned the Spanish to a heavy defeat in Salvador – the first time Spain have conceded five goals in an international game since losing 6-2 to Scotland 41 years ago.
The Spaniards took the lead midway through the first-half when Xabi Alonso converted a penalty after striker Diego Costa was fouled by a clumsy Stefan de Vrij challenge.
However, an astonishing second-half display from Holland saw Louis van Gaal’s side fire in four goals and following Spain’s surprising capitulation, Del Bosque believes that Holland were tactically superior after the break.
"They were better in the second half after a first half when we played well," the coach told Spanish television.
"They looked to knock the ball over the top against our defence and found a lot of space.
"We kept on fighting but they were physically stronger as the game went on and that made a difference."
Del Bosque says his side must now switch their focus to next Wednesday's game against Chile and admits he will have to approach the game with caution.
He added: "It is now a delicate situation for us which we will try and overcome in our next game against Chile and then see what happens."
Midfielder Andres Iniesta admits it will be hard to brush off the defeat, but is confident they will stamp their mark on Group B.
"We have to win the two games that are left. There are small details that tip the balance. But it was difficult for us," said the Barcelona playmaker.
"We are prepared for whatever comes. We'll do our work, but we won't forget about this."