Van Gaal chose Klaas-Jan Huntelaar as his first-choice striker and kept Robin van Persie on the bench, while right back Ricardo van Rhijn was the only new name from the team that lost all three group stage matches at Euro 2012.
"Despite a poor first half performance in ball possession we created six chances," Van Gaal told SBS6-TV.
"Second half we started well with a well-executed building game.
"The personal foul [of Nigel de Jong] was crucial as we were in control and not only conceded the equaliser but also allowed Belgium back in the match."
With a 4-3-3 starting formation and one holding midfielder in De Jong, the Dutch made a stuttering start and fell behind after 20 minutes when Kevin Mirallas set up Belgium striker Christian Benteke to open the scoring.
Despite creating several chances before the break, the Dutch had to wait till nine minutes into the second half for the equaliser when 20-year-old left-back Bruno Martins Indi launched Arjen Robben who set up Luciano Narsingh to score.
A minute later Martin Indi connected with Robben again and the winger found Huntelaar who put the Dutch ahead.
But between the 75th and 80th minutes the young Dutch defence collapsed under the pressure of the passionate Belgian attack.
First De Jong failed to control the ball and lost it to Dries Mertens who equalised and he set up Romelu Lukaku a minute later.
Central defender Jan Vertonghen sealed the Dutch side's fourth straight defeat, their first four-match losing streak since 1954, from a pass by Mertens.
The Netherlands start their World Cup 2014 qualifying campaign on September 7 at home against Turkey, while Belgium travel Wales.
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