Michael Cheika understands well the threat Argentina pose to the Wallabies in their semifinal after almost being wooed into coaching the Pumas.
Cheika held discussions with the Argentinian Rugby Union while on a reconnaissance trip to Buenos Aires after helping plot the Waratahs' drought-breaking Super Rugby triumph last year.
Fortunately for Australian rugby, the Pumas never got their man. But Cheika admits international rugby's biggest improvers have transformed themselves into genuine World Cup contenders since joining the Rugby Championship in 2012.
"Needless to say, they're in the top four of the World Cup so it's the second time for them now and I think that just about says it all," Cheika said.
"They play with a lot of width, but that is set up by a great platform from their scrum.
"They've been developing their play, they are more expansive with good playmakers and they are able to do all that because they have a good base, the scrum."
Cheika says he already had a "close relationship with Argentine rugby", having encountered several Pumas stars during coaching stint at Leinster.
"I'm very close friends with Gus Pichot and obviously [Felipe] Contepomi, [Rodrigo] Roncero, guys I've coached there, Mario [Ledesma].
"I known the coaching staff for a good three or four years. They went on a plan over a few years to expand their game.
"They felt they needed to do that if they wanted to play in that [Rugby Championship] tournament and play in it successfully.
"I think it's proving to be totally validated strategy. They still have their forward platform but they've opened up their backs and they know they have talent there so they're bringing them in.
"They've been developing that game over two to three years now and they're getting the fruits of that labour no doubt."
- AAP