Ireland launch their Six Nations campaign against Wales at the Aviva Stadium on Sunday aiming to avenge a painful 22-10 World Cup quarter-final defeat just four months ago.
And they will start as favourites, if only because Leinster, Munster and Ulster have reached the last eight in the Heineken Cup and showcased the best of Irish playing talent.
"It is good that we have guys coming into camp confident and showing form. That is a big thing," Ireland captain O'Connell said.
"The Six Nations is another level up, but a lot of what we do in the provinces is very similar to what we do here - it's just different calls and with different people.
"The biggest factor is the form guys are bringing with them. They have been playing really well for their provinces, playing high-intensity rugby, and that can only be a good thing.
"When guys are winning high-pressure games, as well, that is a good thing bringing that into the national set-up."
Ireland have won their opening game of a Six Nations season on seven previous occasions, while Wales can reflect on just two victories in Dublin since the tournament's inception 12 years ago.
Ireland lost centre Keith Earls from their plans earlier this week, with Fergus McFadden called up to replace him.
Earls' partner Edel McGee gave birth to their first child, Ella-Maye, last week only for the baby to return to hospital on Wednesday because of an unspecified illness.
And it was decided in conjunction with Ireland coach Declan Kidney that the 24-year-old Munster back should miss tomorrow's showdown.
Wales, though, are without five of the side that accounted for Ireland in Wellington - injured forwards Gethin Jenkins, Luke Charteris, Alun-Wyn Jones and Dan Lydiate - plus record try-scoring wing Shane Williams, who retired from Test rugby in December.
But on the plus side for Wales, World Cup stars Jamie Roberts and Rhys Priestland have been declared fit following knee problems.
"We would have noted the Wales team announcement yesterday," O'Connell added.
"I always thought that most of them were going to play, and I am sure they are delighted that Jamie Roberts and Rhys Priestland are available.
"They were two big parts of their World Cup side with their form in the tournament, so I don't think we have prepared for anything different.
"And Wales have a lot of strength in depth in the second-row. Bradley Davies is an excellent ball-carrier - he's like another back-row forward with ball in hand.
"He is a big powerful guy, and the same with Ian Evans, who is a really good footballer. He has probably been unlucky with injuries in recent years.
"When you think their front two guys (locks) are out, and those two can come in, it shows the strength in depth they have.
"It is the first game of the Six Nations for both teams. There has been a lot of talk about this game since last year's Six Nations and the World Cup, and I would expect an incredibly physical game.
Kidney, meanwhile, claims McFadden's promotion to the starting line-up earlier this week has caused no disruption.
"Fergus has been running at 13 all week, so it is just a mindset for him, really, to get his head around that he is starting, rather than being on the bench. It hasn't affected training at all," Kidney said.
And asked what lessons had been learned from the World Cup loss to Wales, he added: "It is about limiting the opportunities we give others, and exploiting the ones we create ourselves.
"We created enough in that game, we just didn't finish them. Tomorrow will be another good game, like it is between these sides."
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