Cristiano Ronaldo has sent off after elbowing Ireland defender Dara O’Shea during Portugal’s World Cup qualifying match in Dublin — a dismissal that could cost him a place in the opening game of next year's tournament if his team secures qualification.

Thursday's incident occurred just after the hour mark at Aviva Stadium, with Ireland leading 2–0.

Ronaldo swung his right elbow into the back of O’Shea as the two jostled for position.

The referee initially issued a yellow card, but following a video review, upgraded the decision to a straight red.

It was an extraordinary moment for the 39-year-old captain, who has played more than 220 times for Portugal without previously being sent off in a competitive international.

Under FIFA regulations, violent conduct typically carries a two-match ban, which would sideline him for the first game of the World Cup — should Portugal qualify.

Ireland went on to win 2–0 after two first-half goals from Troy Parrott, but the focus of the night quickly shifted to the consequences of Ronaldo’s dismissal.

‘It had nothing to do with me’

Ireland coach Heimir Hallgrimsson later said Ronaldo was wrong to blame him for the red card.

"He complimented me with putting pressure on the referee but listen, it had nothing to do with me, it was his action on the pitch that cost him a red card," Hallgrimsson told reporters.

"It had nothing to do with me unless I got into his head." He added: "This was just a moment of a little silliness for him I would say."

"It's difficult for a player like Cristiano to be in the penalty area," said Portugal coach Roberto Martinez.

"He had constant contact with the defenders, who were grabbing him. There was no violence — he tried to push them away."