Source: BBC SPORT WEBSITE
Argentina have already lost to England in Pool B before bouncing back by trouncing Romania, while Scotland have won their two games so far.
And the Exeter Chiefs winger said: "This match will define a lot of things for us, maybe for Scotland as well.
"Although they have another very hard game against England, I think they can win as well against England."
Scotland have won their last two games against the Pumas, winning in South America last summer when the hosts were missing many of their top European-based players.
"We have played a lot of games with Scotland in the last few years, so we know each other very well I think," Camacho told BBC Scotland.
"They are a very good team and have improved a lot since those games and they beat us in the last two games.
"Next Sunday is our chance for revenge against them and we will try to win. It is a big game for us."
Camacho knows several of the Scotland squad from his time in England's top flight and thought Saracens' Kelly Brown would be particularly important in what he expects to be a battle of the forwards
"The number eight, Kelly Brown, he is a very powerful boy," said the Argentine back, who thought that the Scots had resolved against Georgia the problems that surfaced in their narrow win over Romania.
"They have very good kickers in Paterson and Parks and we have to pay attention to them.
"Both packs of forwards are great and we'll try to do our best to stop them."
Biarritz centre Marcelo Bosch, who has yet to play against Scotland, agrees it will be a tough game but fully expects his side to come out on top.
"It is our most important game in the last four years, so will take the game as a final and we expect to win, of course," he said.
"We know that throughout the year we are perhaps not together a lot.
"But in this period of three months, we have been together and trained for this World Cup and worked on our strategy and technique.
"And I think in the World Cup we are seeing all that stuff that we have been doing."
Fly-half Felipe Contepomi suffered a rib injury in the opening defeat by England and the Toulon man could be a doubt to face the Scots.
However, Bosch said: "I expect him to be on the field. He is our captain and a very important palyer for us."
Venue: Wellington Regional Stadium Date: Sunday 25 September Kick-off: 0830 BST/ 2030 NZ Coverage: Scores and reports on BBC website plus live text commentaries on all home nations matches; updates on BBC Radio 5 live; watch live on ITV1/ITV4, live commentary on TalkSport radio