Japan and Croatia drew 0-0 in the other game in group F which means the Aussies stay in second place in the group and will only need a point against Croatia to qualify, a result Kewell is confident of achieving.
"The belief showed out there on the pitch against Brazil. We closed them down and created chances and it was just disappointing we didn't finish ours," said the Liverpool winger.
"We have taken confidence, although I don't know about that when it comes to me in front of goal but it's just one of those things. You have to look forward to the next game and when you get that chance next time you put it away.
"It's frustrating, because you go out there and play so well against the world champions and you come off losing, when you think you could have come off with something.
"It means a lot for us to get through and a lot to the Australian fans. We're going to be up for it and it should be a cracking game against Croatia.
"I don't think we can go out against Croatia and look for a draw. I think we have to go out and win the game because that's what we do, we don't go out to play soft football, we go out there to win.
"We proved that on Sunday. We weren't afraid to go out and play Brazil and I'm proud of every single one of the boys because they showed what we are really made of."