Wales arrive at the Suncorp Stadium with a dismal record on Australian soil but Deans feels the desire to press their individual claims for a Lions spot next summer could make the visitors particularly dangerous.
"It's a precursor to next year's British & Irish Lions series," said Deans ahead of the third of five clashes with Wales in nine months.
"They know their coach (Warren Gatland) could be the Lions coach and that if they do well out here it will enhance their chances of selection.
"And everyone wants to go on a Lions tour - it's a once-in-a-lifetime opportunity."
Wales have headed Down Under on the back of a third Grand Slam in eight years, while the Wallabies are the reigning Tri Nations Champions.
But Deans saw his under-strength side slip to a surprise reverse to Scotland in atrocious conditions on Tuesday and he admits the Welsh will fancy their chances of avenging December's defeat in Cardiff and October's loss in the Bronze Medal Match at the 2011 World Cup.
"Wales are going to be very excited about what is coming up this month," said Deans, whose team haven't lost back-to-back games since August 2010.
"They have had time together and, having just come out of a season, they are conditioned to the game and they will have had a month's preparation as well.
"They know us pretty well, having played us twice in our last three games, and they will be ready."