'What you shouldn't be sucked into is the complete Super Rugby vibe, where it's almost like a feel-good scenario where we keep ball in hand and run it from everywhere,' he said at a press conference on Monday morning.
'Sometimes it looks on, but it isn't and you get shut down in your own half or you turn your own ball over in your own half.
'Test rugby is a little bit different, the players have a full understanding now about what Test rugby is about.
'All credit to the Irish, they really scrambled and they worked exceptionally hard when they were one guy short.
'But still, we allowed it to look really good.
'We need to really work on our execution, the big positive for me was the amount of opportunities we created.
'When we do the review today, the players will be in a way embarrassed to see that that's what happened and that we couldn't convert.
'Our conversion rate in the Irish 22 was really terrible. It's not to the standard of the Springboks and we know that, but it's something that we really can get right.'
Duane Vermeulen and Lood de Jager sat out training on Monday afternoon, but both are expected to be available on Saturday.
While he praised Ireland's effort, Coetzee was less than impressed with Joe Schmidt's game-plan.
'In Super Rugby we really talk about a ball in hand approach and use it, but there are times when we have to kick it and that balance is the key,' he said.
'There's a place for the kicking game and if you look at how the Irish put us under pressure, actually we did dominate territory but by a small margin.
'But they weren't interested in playing. All they did was make it as difficult as possible for us to exit, just put it in behind us, turn us and we were actually bogged down in our own 22 there.
'They got a drop goal and a chip try and it was a very clever tactic and I don't think we handled it well but I think we will be better this week.'
