O'Brien wants more from Ireland

Ireland flank Sean O'Brien urged his side to go to "bigger and better things than this" after they set up a World Cup quarterfinal against Wales with a 36-6 win over Italy.

Man-of-the-match O'Brien was a commanding figure at the Otago Stadium in Dunedin on Sunday as Ireland proved too strong up front and too smart in the backs for Italy in booking a last eight clash against old foes Wales in Wellington on Saturday.

Ireland, who've won all four of their matches at this World Cup, have now gone one better than the 2007 French edition where they were knocked out at the group stage.

However, no Ireland side has ever reached a World Cup semifinal and O'Brien, who plays for European club champions Leinster, said: "We feel good. We've done our job and topped the group.

"But this squad of players isn't happy with that. We want to do bigger and better things than this.

"There's way more to come from this team.

"We said after the second pool game we're halfway there and now we'll say again, we're only halfway there.

"There's no point thinking we've achieved something now because we've done what we've done.

"Obviously it's good, but we still want more and Wales is next on the list. Hopefully, we can take it up a notch.

"There's a big week ahead of us and we'll certainly be holding nothing back," he added.

Had Ireland, who beat Australia 15-6 in one of the upsets of the tournament so far, lost to Italy they would have been on their way home.

But after a hard-fought first half, which ended with Ireland leading 9-6, they scored 27 unanswered points after the break as skipper Brian O'Driscoll and wing Keith Earls, who grabbed a double, crossed for well-worked tries.

"It's tough to come into a game knowing that nothing other than a win will do," said O'Brien.

"We stuck to our guns and our game plan and it paid off. We never strayed from what we meant to do.

"There's a great mixture of youth and experience in the squad," the 24-year-old loose forward said. "The experienced lads you follow in big games like this.

"It was a good game. It was physical and fast -- everything you wanted.

"We were all about being direct in this game and things opened up for us."

O'Brien briefly attracted a few wolf-whistles from the massed ranks of Ireland's female fans in the crowd on Sunday as he changed shirts.

But he insisted it was nothing like the moment when highly-toned New Zealand centre Sonny Bill Williams removed his jersey in the All Blacks' tournament opener against Tonga.

"I don't think I'm in as good a shape as Sonny Bill Williams!" he said.

"I was trying to get the shirt on as quickly as possible. I was struggling to get it on. I'm weighing in a bit heavy at the moment."

AFP