Argentina second row Tomas Lavanini was sent off in the 18th minute of his side's Rugby World Cup match against England on Saturday.
Lavanini was shown the red card for a high tackle on centre Owen Farrell. England were leading 5-3 at the time.
"We have clear foul play," said referee Nigel Owens.
We have clear contact with the head. There's a shoulder to the head. I am not seeing enough of a mitigation in my view - the player has not come down a considerable amount of height for the tackler to avoid a red card.
Argentina went into the game in need of a victory if they were to secure a spot in the quarter-finals.
It is the second time a player has been sent-off during the tournament for a dangerous tackle on Farrell. Cork-born John Quill, who plays for USA, saw red during his side's opening game against England.
18: Red Card!
"Clear foul play, clear contact to the head. I am not seeing enough mitigation"
Argentina are down to 14 as Tomas Lavanini is sent off for a high tackle on Owen Farrell.
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