Van der Vaart replaced the injured Wesley Sneijder late in the first half and then broke the deadlock early in the second half with his 22nd international goal on his 104th appearance.
A 3-0 victory gave the Dutch a maximum 15 points from 15 in World Cup Group D qualifying ahead of Tuesday's home game in Amsterdam against Romania, who trail the pacesetters by five points.
With Sneijder out with a groin injury, Van Gaal has added Adam Maher to his squad but Van der Vaart is hoping to again seize his chance.
"I felt good to be important for the team and to show that I am still around," said the 30-year-old.
"I know that Sneijder is Van Gaal's first choice and I can live with that, but my goal is to turn that around and become first in line."
Sneijder and Van der Vaart are both products of the Ajax Amsterdam youth academy who also played together for Real Madrid but Van Gaal cannot find a place for both in the same team.
He fielded both in his first match of his second spell as national coach in August last year but a 4-2 defeat by Belgium convinced him he must play one or the other.
"Both are not capable of delivering the required defensive work so only one of them can play," he said.
Romania will be without midfielder Costin Lazar, who sustained a thigh injury a day before the 2-2 draw with Hungary on Friday, and key defender Dorin Goian who is suspended.
Florin Gardos is set to deputise for Goian, forming a partnership with his Steaua Bucharest team mate Vlad Chiriches in the heart of the defence.
Piturca is expected to make several other changes to his starting line-up with Razvan Rat, Alexandru Chipciu, Raul Rusescu and Alexandru Maxim set to come into the team.
Veteran striker Adrian Mutu could become Romania's all-time leading scorer if he hits the target on Tuesday. The 34-year-old netted his 35th goal against Hungary, equalling Gheorghe Hagi's record, set in the 1990s.
Netherlands: Kenneth Vermeer; Darryl Janmaat, Stefan de Vrij, Bruno Martins Indi, Daley Blind; Kevin Strootman, Rafael van der Vaart, Jonathan de Guzman; Jeremain Lens, Robin van Persie, Arjen Robben
Romania: Ciprian Tatarusanu; Gabriel Tamas, Florin Gardos, Vlad Chiriches, Razvan Rat; Alexandru Bourceanu, Doru Pintilii, Alexandru Chipciu, Raul Rusescu, Alexandru Maxim; Adrian Mutu