Coach Joe Schmidt said Bundee Aki was "devastated" by his first-half red card after Ireland beat Samoa 47-5 to book a World Cup quarter-finals spot.

Centre Aki's 29th-minute dismissal for a high hit on Ulupano Seuteni came when Ireland led 21-5, but they did not concede for the rest of the game.

Aki, 29, is of Samoan descent and was clearly upset as he left the pitch.

"We are happy with the result and performance but disappointed we didn't finish with 15 players," said Schmidt.

"It's devastating for Bundee. He knows the Samoan players really well."

Aki's World Cup could be over following his red card and he faces an anxious wait to see if he is handed any further sanction.

Earlier, Samoa hooker Seilala Lam had been yellow-carded for a similar high shot, but he had tried to lower his point of contact while Aki remained upright and referee Nic Berry ruled there was "a high degree of danger".

"I rate Nic Berry and I think he is a very good referee, so it is hard to argue at the moment," added Schmidt.

Samoa were almost as distraught as the Irish over Aki's red card and coach Steve Jackson said they would willingly make representations to help the 29-year-old escape further sanction.

"I hope no further sanction goes on," said Samoa coach Steve Jackson, who lost two players to red cards through the course of the tournament.

"I've known Bundee for a long, long time, he's a great man with great character.

"Hopefully the powers that be see some sense and he gets to continue on in the tournament because he's a great kid."

Ireland captain Rory Best said they had been mindful not to panic following Aki's premature exit.

"We had to leave some defensive rucks alone and make sure we had numbers on feet," said the 37-year-old hooker.

"We've overcome red cards before. It's never ideal but it shows a lot of character about a squad that whenever you go down a man, how you adapt to that.

"Ultimately there was no panic. There was a lot of collective. We just continued to attack them."

Best said that the team's display in the seven-try win "maybe wasn't that pretty but it was effective".

"After the Japan game we knew 10 points would get us through, and we got that. The boys rolled up their sleeves.

"The big thing is that we never panicked [after the Japan game]."