The reigning champions suffered a woeful start to the defence of their trophy when they were beaten 5-1 by the Netherlands in their opening Group B game, while Chile overcame Australia 3-1.
However, Vidal insists that he and his team-mates will not be taking Spain lightly when they meet in Rio de Janeiro, with Vicente Del Bosque's side out to prove a point.
"It will be a difficult game," said the Juventus man.
"They are the champions. They had a very tough loss (against the Netherlands), (which was) maybe a little unexpected because they were also winning.
"We watched the first half before heading to the stadium (for the Australia match) and we know they'll come with a lot of anger when they play us, because they have to win to avoid being eliminated.
"So we hope to be up to their level. They have always been dangerous. They are defending champions for a reason, but no one expected that game with Holland."
Vidal was considered to be a doubt for Chile's opening match due to a knee injury and although he was included in the starting XI, he came off in the second half.
The substitution was purely cautionary, however, according to the 27-year-old, who is aiming to be fully fit to face Spain.
He added: "I have to see how I feel. I want to get 100 per cent before the match with Spain.
"I hope I can be at one hundred (per cent) to help the team. We need to get three points again and move forward."
