The Bosnians, beaten 1-0 in the first leg in Lisbon on Saturday, will be without three key players through suspension but Blazevic is confident a thunderous atmosphere, and the ferocity of his players, can see them pull off a huge upset.
"We will launch an onslaught like hungry wolves from the start and I am certain that Portugal will be stunned by the atmosphere," Blazevic was quoted as saying by daily Dnevni Avaz.
"What we need is not support, but a thunderous roar from the terraces that would put all the pressure in the world on the Portuguese," he added ahead of a match that will decide which team goes through to the World Cup in South Africa next year.
Defender Bruno Alves, the scorer of Portugal's winner on Saturday, is nursing a sprained ankle and playmaker Deco has a groin strain but both are likely to be fit for a stern test in the cauldron of the Bilino Polje stadium.
"They (Bosnia) will open up more and we are going there to score, we've got to have that idea," he said.
"It will be a game of great emotions, the devil will be behind the door in every chance as risk and errors will walk hand-in-hand.
"We have to hold the ball more and control the game, be cold as we impose our own rhythm and intensity."
