Rob Kearney insists RBS 6 Nations champions Ireland must improve to avoid getting left behind by the best teams in world rugby.
Ireland lifted the RBS 6 Nations title in March with a 22-20 victory in France, before recording back-to-back wins against Argentina this month.
However Kearney is not satisfied with the level of performance shown by Joe Schmidt's side in those two contests, which finished 29-17 and 23-17 respectively.
And with a World Cup just a year away, the full-back is worried by the prospect of New Zealand, England and South Africa making greater strides than the Men in Green.
"We played poor enough, we turned over a lot of ball, our rucking was poor," he said.
"We had a huge amount of possession, but we lost a lot of rucks and it was hard for us to build phases, keep the ball. Still, two from two is not a bad result for us.
"We always try and judge ourselves by performances, while results are important. If we are striving to be proper World Cup contenders then you have to judge yourself on performances. So I suppose it's between the two. The World Cup is still a long way away, but that's what we're striving to do.
"We want to build a squad here that can be World Cup contenders, we've always said that on our day we can match or beat the best. But the standard is increasing right across the world.
"New Zealand are getting hard to beat, the English are getting strong and South Africa bashed Wales. We have to keep evolving and improving because, if we don't, we'll be left behind."
England Under-20s head coach Martin Haag was full of praise for his World Rugby Under-20 Championship-winning side after Harry Mallinder inspired them to a 45-21 win over their Irish counterparts and a third title in four years.