Head coach Milovan Rajevac was suspended for the final Group B game after being sent off in the previous game against Libya.
Appiah took charge of the game in Bouake despite having instructions from the head coach via a mobile phone during the game.
The former Ghana international revealed that even though it was his first time in charge of the side at a major tournament, he was not under pressure.
“I have been a player before, and I have been in charge of big matches, so I was not under pressure at all,” Appiah told KickOffGhana.com.
“We were told that coach Milo would not be allowed to be on the bench 24 hours before the game, so we planned very well.
“We thought through the strategies before the game, as we have worked together for a long time.
“As and when it was necessary I had assistance from the head coach, which made it even better.”
Ghana will meet Senegal in the last four in Bouake while DR Congo travels to Abidjan to face Group A winners Zambia.
