Spain coach Vicente del Bosque fielded an experimental side at the Amsterdam Arena with Iniesta, who started on the bench, entering the fray in the 76th minute to chorus of jeering and boos from the home fans.
Centre-back Stefan de Vrij and midfielder Davy Klaassen scored first-half goals in the morale-boosting victory, but Hiddink was unimpressed with the way Iniesta was treated.
''It's a disgrace,' said the Oranje manager. "He's a world class player and a wonderful person. At first I didn't notice it was about him. Was it because of his goal against the Netherlands in 2010? It's unbelievable, this is about sport. What was he supposed to do? I can't understand this.''
Tuesday night's friendly win was a much-needed boost for Hiddink who has endured a tough start to his second stint as national coach, especially following the 1-1 draw against Turkey on Saturday from a last minute Wesley Sneijder goal.
Following the pressure the manager took following his second stint as manager to a poor run of qualifiers for the European Championships in France next summer, Hiddink truly has had enough of the critics. ''I don't have the feeling that there is pressure on my shoulders. I don't want to fight against the media any more, I just want to stay focused on football. There are always stories in the press.''
He is hoping to focus on qualifying with remaining matches to finish off the year and hope to make a successful run in a major tournament just like his predecessor and current Manchester United manager Louis van Gaal, where he took his Dutch side to third place at the 2014 FIFA World Cup in Brazil last summer.