He believes that fine margins divided success from failure, with key incidents in games not going the way of the Celts when it counted.
“We were so nearly there,” he told Love Rugby League.
“There were opportunities we didn’t take, that if we had taken, games would have been a lot different.
“The Italy game, for example, if we had taken some of those missed opportunities then it could have been a different result.
“But everybody wanted to put the red shirt back on, go out there, and replay the game.
“It was disappointing, but we will learn from it, and next time round we hope we can put it right.”
The passionate backing of the Welsh fans at the Millennium Stadium, though, is something which will live with Kopzcak for a long time.
“It was fantastic to lead them out, and then sing that anthem,” he added.
“The crowd really got behind us, too, singing along. It put us in good stead for that game, but unfortnuately we couldn’t capitalise on it.”
“Those big games do help. You do need experienced players, and we will get them. They are coming through. We’ve got some now at Wigan, and at Widnes.