The midfield pair believe their team has what it takes to worry the powerhouse sides they are set to come up against, despite having been written off by most observersWorld Cup.
The Socceroos are settling into their tournament base camp in Vitoria this week, and on Friday will undergo their first training session as they resume intense physical and tactical preparations in readiness for matches against Chile, the Netherlands and Brazil.
Versatile Brisbane Roar man McKay believes the attention to detail shown by head coach Ange Postecoglou and his backroom staff will stand the team in good stead for the daunting fixtures ahead in Group B.
"The Aussie fighting spirit, you want to prove people wrong and if we can do that it would be great," he said.
"A lot of things have to go right for us but if we prepare properly and Ange will have us prepared properly. The video sessions and stuff the assistants put on have been great, so we will be there or there about and hopefully surprise a few people."
Vidosic, who plays his club football in the Swiss Super League with FC Sion, echoed the sentiments of his team-mate, insisting Australia are not there just to make up the numbers.
"We are confident as well, you know it is a very nice challenge to have and the best things in life are never very easy," he said.
"We have a great challenge ahead but we want to be challenged and we want to play against the best in the world.
"At a World Cup regardless what group you are in, you are going to play against the best in the world because the best 32 teams qualify for the World Cup. We know we have tough games ahead but we want to make it tough for them as well."
The Socceroos play Croatia in a friendly next Friday ahead of their tournament opener against Chile on June 13.