Van Gaal defends Dutch violence in 2010
The Dutch were widely lambasted four years ago in South Africa for their physical approach in the final in Johannesburg, which Spain won 1-0 in extra time.
In a performance that was in direct contrast to the traditional Dutch style of football, the Netherlands - under then coach Bert van Marwijk - tried to knock Spain off their game with referee Howard Webb dealing out five yellow cards in the opening half-hour, including three to the men in orange.
Nigel de Jong's flying kick to Xabi Alonso was the most controversial with Webb later admitting he should have shown a red card to the Dutch defensive midfielder.
In all, eight Dutch players received yellow cards at Soccer City - compared to five from Spain - while John Heitinga was shown two to be sent off in extra time.
On Friday, Spain and the Netherlands will meet for the first time since the 2010 final and when challenged about Van Marwijk's rough tactics on Thursday, Van Gaal claimed they were legal and did not rule out employing them again in the Group B encounter.
"I believe that physical resistance is part and parcel of football," Van Gaal said.
"There is a referee that will point out what the limits are and I think the team four years ago did not cross the line.
"It is obvious you have a different opinion, which is a shame. I think the physical struggle is part of football. It is part of sport. If you watch our training sessions you can see it for yourself, in the structure and process we have."
The 62-year-old, who will take over at Manchester United after the World Cup, added his impending job was helping him focus on the task at hand in Brazil.
"The World Cup is a championship and clubs don't take part in this, so I am fully focused on the national team," Van Gaal said.
"Distraction? It may be a distraction but, for instance, the players - when was it? - on Monday afternoon and Tuesday morning, I gave them some time off, just to get out there.
"You can't just focus monotonously on the World Cup, so perhaps Manchester United was a good distraction. You can't be fully focused on football for five weeks."
De Jong and Alonso are both expected to play at the Itaipava Arena Fonte Nova in Salvador on Friday.