The Porto FC player did not feature much against the Democratic Republic of Congo in a Group B match which ended 2-2 after after Ghana had led 2-0.
Appiah believes he will settle down soon and show why teams like Tottenham Hotspurs are chasing him.
“Atsu is one of the young talents that every Ghanaian relied on to start very well in such a competition,” Appiah told MTNfootball.
“Most of the time, you could be the best player in the world but once you go into a competition that you have not been in before, you may start slowly.
“I have been talking to him yesterday (Sunday) and today (Monday) and we need to raise his confidence level and psyche him up.
“And I believe that even though we did not have a good game yesterday (Sunday), along the line you will see the real Atsu.”
Atsu is one of 10 players making their AFCON debut