After their loss to the United States, the Socceroos face the world's 37th ranked side in their final group D match in Santa Clara on Thursday (Friday AEST) with everything to gain.
Win or draw, and Tony Popovic's charges will finish second and head to Dallas to face the group G runners-up -- one of Belgium, Egypt, Iran or New Zealand.
Lose, and Australia face a nervous wait to discover if they're one of eight best third-placed teams to progress.
The only problem? Australia have struggled against South American opposition.
Since beating Ecuador 3-1 in March 2023, the Socceroos have lost to Ecuador again, Argentina, Venezuela and Colombia.
"Listen, it is just a totally different type of game. We all know that in the games we've played against South American teams in the past," said the vastly experienced midfielder Irvine.
"Watching Paraguay against Turkey, there was a sequence towards the end of the game that kind of sums up their style of football.
"It was with about five minutes to go. They won the ball back high up the pitch, and they had a chance to go to the corner, and the guy just whips the cross in to the back stick with three men and they go on and try to score again with 10 men, when they're 1-0 up.
"You know what kind of game it's going to be. They have incredible individual quality, as you saw in some moments, and you expect the unexpected, I guess that's probably the best way to put it."
Paraguay will be without gun midfielder Miguel Almiron, who will be suspended after becoming the first player sent off at a World Cup for covering their mouth during a confrontation.
The Socceroos lost to Colombia 3-0 and Venezuela 1-0 in November, games that served as warm-up matches for this experience.
"There are lessons to be learned there. Particularly against Colombia, for an hour we looked really comfortable with the ball," Irvine said.
"Especially from back to middle, really good in possession, breaking that first two lines, but we probably didn't find a way to create any real clear-cut chances in that game.
"So we know that tactically we're going to be very good within these areas, it's just about being clinical, because we know that that's where these teams thrive - as well as being clinical in the final third.
"That style of play - the technical quality and unpredictability of it - is tough to defend against as well.
"So we have to be switched on for that within our structure, but then find our ways to hurt them as well in the final third."
