The Bayern Munich winger had some surprising words of praise for his coach after Netherlands secured top spot in Group B with a 2-0 victory over Chile in Sao Paulo
Van Gaal - who will take over as Manchester United manager when his World Cup commitments come to an end - has guided Netherlands to top spot in a Group B containing Chile, Australia and reigning world champions Spain.
The Oranje qualified as group winners on Monday after a 2-0 win over the South Americans in Sao Paulo, with Van Gaal's substitutes Leroy Fer and Memphis Depay scoring the decisive goals.
And, after the match, Robben - who collected his second successive Man of the Match award in just his boxer shorts - had some surprising words of praise for his coach when addressing the Dutch media.
"Maybe Louis does have a golden willy," he replied smiling when asked about the impact of Van Gaal's substitutes.
When Robben's comment was put to him, Van Gaal replied: "I don't know. Truus [his wife] has never told me that!"