Australia national team captain Lucas Neill is confident that there is still further improvement to come from the players.

Following the Socceroos' 1-0 World Cup warm-up friendly win over Denmark in Roodepoort, Neill was sure that things would get better in Saturday's clash with the USA before the tournament proper.

"(The performance) is still not brilliant but some good things we did out there defensively. We've been working on keeping a high line, keeping an organised shape and overall I think we did that very well because Denmark had some decent movement," he told Fox Sports after the game.

"We need to be 98-99 percent by Saturday because we want to make sure we are as good as we can be going into Germany (first group stage) game. I think we are 90 percent now fitness-wise, there are still a few good touches that need to be produced but we will work hard again for the next couple of days and (against) the USA we will give it as much as we can with the sharpness."

Neill also touched on the positives from the game which were the fact the Socceroos continued their winning ways.

"One-nil, a clean sheet, starting to look very fit and we are only going to get stronger," he said confidently.

The conditions were foreign to the Australians as they were playing at high altitude and the ball was swerving around everywhere but Neill said that was a factor they had to deal with, just like everybody else.

"The pitch was very beachy, the ball obviously moves a lot but it's going to be the same for everyone. We've just got to learn to adjust, learnt to take it as it comes and overall I think we did well," he added.