Ireland coach Joe Schmidt has warned Canada pose a serious threat to his team's Rugby World Cup ambitions.
The Irish are hot favourites to win an opening Pool D tie against the world's 18th-ranked team on 19 September.
Schmidt fears Canada could prove "an incredible banana skin" for his team.
There is a temptation for Ireland to mix up selection for the World Cup opener, ahead of games with Romania, Italy and the hugely important showdown against France.
Ireland are heavily backed to progress to a first-ever World Cup semi-final, but Schmidt remains cautious ahead of the opening clash with Canada in Cardiff.
"I know that people probably won't see them in the same light, but I think they are an incredible banana skin for us," said Schmidt.
|Ireland's World Cup pool games|
|Saturday, 19 Sept, 14:30 BST: Ireland v Canada, Millennium Stadium|
|Sunday, 27 Sept, 16:45 BST: Ireland v Romania, Wembley Stadium|
|Sunday, 4 Oct, 16:45 BST: Ireland v Italy, Olympic Stadium|
|Sunday, 11 Oct, 16:45 BST: Ireland v France, Millennium Stadium|
"You don't have to look back too far to 2007 and assumptions can undo teams very, very quickly.
"We're not assuming anything other than Canada will be right up for the game."
The dismal showing in 2007 remains the only time the Irish have failed to progress from the World Cup pool stages.
Argentina and hosts France qualified at Ireland's expense eight years ago, and Schmidt is determined his class of 2015 will not befall a similar fate.
"I just think the threat across the backline that they have, it could be one of those games where if it's a bit dour up front and it's hard to get a lot of success there, you don't need to invite (Jeff) Hessler or Van der Merwe into the game too often for them to have a pretty serious impact on the scoreboard.
"So from that perspective we just don't feel we can afford to take chances."