With a win or draw at Levi's Stadium in Santa Clara on Thursday (Friday AEST), Australia will finish second in group D and face the Group G runners-up - one of Belgium, Egypt, Iran or New Zealand - in Dallas.
Defeat would mean a nervous wait, but they could still progress as one of eight best third-placed teams with a possible clash against Group E winner Germany in Boston.
A draw would realistically send both teams through, but Paraguay would love to snatch a win and seal second place.
A more open game style would suit the Irankunda-Mohamed Toure-Connor Metcalfe attack that tore up Turkey.
Even Paraguay coach Gustavo Alfaro is expecting Australia to have less possession, then cause chaos on the counter.
But Popovic wasn't biting on how Paraguay's search for three points could make for a more open game.
"We haven't thought about the game in that way at all," Popovic said.
"We're going into the game tomorrow to win. I expect they'll be doing the same.
"I can't speak for them. I can only speak for us. To be in this position, third game, in our hands to go through, it's a great position to be in."
Alvaro has his own headaches in trying to negate the aerial strengths of Australia's tall timber in Harry Souttar, Cameron Burgess and Alessandro Circati.
But Popovic, who had his team play South American opposition in Colombia and Venezuela as preparation last year, is wary.
"We understand what they bring. They bring a real toughness," Popovic said.
"Their qualifying in South America is very difficult.
"They know how to get a result. They showed that in the last match (against Turkey), scoring early, 10 men, and they're really resilient and tough, fantastic manager, lot of experience.
"It's a wonderful challenge. It's what we're here for.
"We love the position we're in, that we can go through to the next stage, the knockout stages and we know it's in our hands and we know what a win does for us."
Popovic knows there is creativity - via the "fantastic" Julio Enciso - and grit in this Paraguay team.
"Paraguay are very strong. They're here because they deserve to be here," he said.
"They're at the same stage as us, where they are fighting to go through to the knockout stages.
"We have a lot of respect for them, but we're also very confident in our ability."
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