Vidal fit for Chile's 'final' with Aussies
Chile's national football team midfielder Arturo Vidal rests on the ground during a training session at the Toca da Raposa training ground in Belo Horizonte, on June 11, 2014 - by Martin Bernetti
Vidal's presence could be vital as an opening win in Cuiaba would put either side in a position to challenge Group B giants Spain, the reigning champions, and the Netherlands for qualification.
The 28-year-old Juventus midfielder's participation was in jeopardy after struggling with an inflammation to his right knee following surgery on a meniscus problem last month.
But allaying a nation's fears, Sampaoli disclosed that the dead-ball specialist's troubles were behind him.
"This story's over I think. The physio's done a marvellous job, Vidal's diagnosis is clear, there's a high chance he'll play.
"His injury was rather complicated. We will now make a decision on whether he starts on the pitch, or on the bench."
Chile, who came third in South American qualifying, want to translate some excellent recent results into a long run at this World Cup, especially after falling to Brazil in the Last 16 in 2010.
In Australia, Chile face the lowest ranked team at the finals, but Sampaoli is anticipating a tough encounter.
"This is really a first final for us against Australia. Our margin for error is small.
"We believe Australia will wait for us and counter. I need my players to be nimble and quick to break through strong defences."
Asked at the pre-match press conference about the prospect of the more imposing Socceroos taking a physical approach, the Chile boss replied: "The physical approach, that was their history.
"I think their new manager has coached them differently, instead of being physical it'll be a different kind of duel.
"Australia are a difficult team, they've changed their set up, they come here without pressure.
"Whereas for us we must face nervousness and pressure.
"Their style can be rather complicated if we have an off day, I think we've got a really tough match ahead."
The Argentine, whose high pressing style of play has won Chile many plaudits as well as matches, says Vidal, Alexis Sanchez and company are here to do business.
"We're hungry, we want to go beyond our present performance level.