Most members of the US women’s soccer team stayed silent during the national anthem before its World Cup opener Friday against newcomers Vietnam — who passionately belted their nation’s tune.

The majority of the reigning women’s World Cup champion team stared stoically ahead as the “Star Spangled Banner” blasted across New Zealand’s Eden Park arena.

Only five of the 11 players who stood on the field for the anthem — with young, aspiring players standing before them — placed their hands over their hearts, while their six teammates kept their digits clasped behind their backs, video shows.

Only three USWNT players — Julie Ertz, Alyssa Naeher and Lindsey Horan — sang along with the hundreds of American supporters watching in the stands.

Comparatively, members of World Cup debutant Vietnam emphatically crooned their national song “Tiến Quân Ca,” or “Song of a Marching Army.”

All 11 players passionately sang along to the anthem in unison, with their right arms precisely held over their hearts.

The coaches and fans passionately joined the chanting for the first time their national song was ever played at the FIFA Women’s World Cup.

In spite of their competitor’s apparent charisma, the USNWT team decimated Vietnam 3-0 in the team’s historic game.

The two-time defending champions went into the opening match looking to set the tone for what they hope to be their third-consecutive title clinch.

The women’s USWNT team has a complicated history with the national anthem.