Ireland's 24-9 World Cup win over France has been marred by a punch from flanker Sean O'Brien on Pascal Pape in the first minute of the match and might see him miss their quarter-final against Argentina.
O'Brien lost his cool and took objection to Pape holding onto his jersey. It prompted the Irishman to land a powerful punch into the Frenchman's stomach which knocked him to the ground.
Medical staff attended to Pape, who appeared in real discomfort after the hit.
The incident will likely catch the attention of match officials and might result in O'Brien missing his side's important clash with Argentina.
Pape is no stranger to controversy when it comes to playing Ireland. He was banned for 10 weeks earlier this year for kneeing Jamie Heaslip in the back and fracturing his vertebrae during a Six Nations game.
O'Brien's availability for the next game is not the only concern for Ireland as Jonathan Sexton and Paul O'Connell were both injured during the win over France at Millennium Stadium.
Ireland coach Joe Schmidt said post-game he could not afford to lose his flanker and man of the match.
"I certainly hope not," Schmidt said when asked if he thought O'Brien should miss a game. "He was being held at the time and he swung. I don't think he's looking directly at the player. But it's not for me to determine. I also think that it's not a closed fist.
"I'd be hopeful but it's not a decision for me. Hopefully it's not a decision that impacts on us considering the dressing room at the moment with the amount of injuries we have we can ill afford to lose another player, particularly a player of Sean's experience and standing in the group."
