Seeing the USA as favorites in the group and perhaps Vietname as the easier target (maybe?), this would always be the decisive game for both NL and PT, I guess. The Netherlands has much more experience than Portugal in Euros and World Cups since this is the first participation for Portugal but I understood they are undergoing a renewal in the squad (?).
This to say that it seems normal for both teams to approach this game carefully. I only watched the last 30 minutes when NL was defending the victory but PT could not create any good chances.