The goalkeeper was introduced in the closing minutes of the Dutch's game against Costa Rica at the tournament in Brazil – saving two spot-kicks to help his team progress – and revealed how manager Louis van Gaal informed him of the plan on the way to the game.
Krul told FourFourTwo magazine: "Only me, the goalie coach and the manager knew of the plan before the Costa Rica game. Louis van Gaal pulled me to one side just before we stepped on the bus to the stadium. He asked me to be ready if it went to extra-time and penalties.
"Truly, I didn't think it would go to penalties, but we kept hitting the crossbar and the post, and it went to extra-time. I had to get warmed up, and I told Van Gaal I would be ready with two minutes to go, because I had to obviously get on the pitch before the final whistle went.
"I'd studied their penalty takers, but I didn't have notes. It was all in my head and then feeling the moment. There was definitely big pressure, but what an honour to see everyone run towards me after the win. I dreamt about that as a kid."
The Dutch were beaten on penalties by Argentina in the semi-finals and Krul explained that Van Gaal regretted not bringing him on again for the clash against the South Americans.
The former Newcastle player said: "Apparently, after my heroics in the quarter-finals, that's Van Gaal's biggest regret, that he didn't put me on instead of Klaas-Jan Huntelaar.
"But Robin van Persie was injured and there was still most of extra-time, so I understand why he put a fresh player on. To save Lionel Messi's penalty in the semis would have trumped the quarter-finals. It wasn't to be, but I'm proud of what I achieved."