But looking ahead to their next game against France, he said they could at least take some heart from the way they fought back in the final quarter, scoring two tries through replacement centre Tom Shanklin.
"It's one of the most physical games I have played in for Wales," said the Celtic Warrior."They came at us and it just seemed to be like a tidal wave. Their forwards would bring the ball forward and the backs would be steaming on to it. It's very hard to stop that.
"It felt like a steamroller. They had dominance in the rolling maul and their backs gave them targets to work from. The pace of the game wasn't that much greater than other internationals I have played in, it was just the physical aspect of it.
"The Irish forwards really got stuck in and battered us about a bit. The ball I received was quite clean. The problem is that ball needs to be taken forward at some stage to gain momentum and we didn't seem to be able to do that.
"At times I felt we did play a bit laterally. We knew we had the wind in the second half and we were disappointed we conceded a try early on after the break, which was a big blow to us, having turned round 24-3 down."
Wales missed a total of 10 tackles in the face of intense pressure from their hosts and Cooper admits the defence wasn't as good as it has been of late.
"We leaked a few times through the breakdown area," he said. "Perhaps we were below par in defence. But it is difficult when the opposition has got such a momentum up."
One man who caused Wales particular problems was Ireland skipper Brian O'Driscoll, who marked his return from a six-week injury lay-off with two tries in a 36-15 triumph."O'Driscoll is a very special player," said Cooper. "Considering he has been out for six weeks it didn't show. Perhaps he was a bit fresher if anything."
"The message from within the camp is still to stay positive," said Cooper. "We knew we weren't the finished article and that we had a long way to go. Perhaps we didn't play as well as we could in this match and didn't improve on last week's performance against Scotland, but hopefully in the next game against France we can improve again.
"We have had some good performances in the last few games and dug in right to the end in this match. We could have gone into our shells and lost by 50 points. We did fight back and tried really hard but things just didn't go right for us at crucial times.
"Fair play to the boys, they did get stuck in and battle right to the end of the match. There were still positives to take out of the game, particularly the work rate of the boys in the second half. It was good seeing we were so far down. We could have caved in, but we didn't do that.
"It has been an intense fortnight. We will go away now and analyse the video of this match. We will work hard this week and then next week build up to the France game."
Cooper, who won his 17th cap yesterday, expects the French to have a few tricks up their sleeve when they come to Cardiff."They had a great win against Ireland and you've seen how good the Irish were in this game against us," said the 24-year-old. "For France to have beaten them shows how good a side they are.
"I am sure they were a little bit relaxed against Italy on Saturday. Perhaps their coaches told them not to use any of their strike moves, because they didn't seem to use many moves.
"I am sure they will try to bring some surprises to us."
Simon Thomas, The Western Mail.