Ghana face a tough challenge to replicate their run to the 2010 quarter-finals at this year's tournament, having been drawn alongside Germany, Portugal and the United States in Group G.
But head coach Appiah is taking heart from his side's attitude to the task that awaits them in Brazil.
"The unity is so great and discipline is very high," he said ahead of Saturday's match against the Dutch in Rotterdam. "Discipline plays a big role, if you want to be successful, 100 per cent lies with the players' behaviour and so far it has been good.
"There is this kind of competition, no one is sure of himself at the moment. Everybody is attentive to whatever is taught in training. Everyone tries to do whatever he can and for me, it's good for the team and I am really impressed."
Defeat to Montenegro in their last game will have given Appiah some cause for concern, with Dejan Damjanovic's first-minute penalty settling matters in Podgorica.
Coach Louis van Gaal has already been confirmed as Manchester United's next manager and will want to sign off from international duty in style.
They will have a chance to take revenge on the side who beat them in the 2010 final as Spain are the Netherlands' first opponents in Group B.
