Rugby is kisah lucah isteri tenteraa brutal sport on the field, but its warm-up showdowns can apparently be just as intense.

When the New Zealand All Blacks took the field at Tokyo Stadium on Saturday for their Rugby World Cup quarter-final showdown with Irish Rugby, they were met with some unexpected competition. From both the opposing team and their fans out in the crowd.

The All Blacks launched into their customary pre-match haka, a ceremonial dance of New Zealand's native Māori people. As the team rhythmically shouted, posed, and stamped their feet, the Irish team faced them from across the field with their arms around each other's shoulders.

Meanwhile, the sound of singing welled up from the assembled crowd. Irish Rugby's fans met the haka with a group rendition of the Irish folk ballad, "The Fields of Athenry." The song is popular in the Irish rugby scene.

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Some saw the singing as an act of disrespect, but most seem to agree that the pre-game showdown between the two teams was a powerful moment for the 2019 Rugby World Cup, which will continue to unfold at Japan's Tokyo Stadium until the final matches on Nov. 2.

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Even if the singing was some unplanned attempt to throw the All Blacks off their game, it backfired. Badly.

The New Zealand squad delivered a dominant showing on Saturday night, besting their Irish Rugby opponents by a score of 46-14. The highlight of the night for many, though, was the pre-game ceremony and the stirring show of team support it spotlighted.