This is exactly the type of victory Netherlands needed. One where they played averagely, defended with mediocrity, fought with sweat and resource, underwent tactic modification and still managed to make a comeback and win through individual brilliance.
Psychologically, this will boost them that they can both win against the strongest favorites like Spain through teamplay and tactical coherence as well as highly-spirited underdogs like Australia through luck and talent. This win will also give them much-needed confidence but altogether put all players who were still too much on cloud nine after Spain's victory back to Earth. Also, players who did not perform up to their level like Sneijder and especially De Guzman will surely be forced to step up, considering Van Gaal's nature.