Gyan had a chance to send Ghana to the semi-finals of the World Cup from the penalty spot with the final kick of extra-time.
But Gyan blasted his penalty against the crossbar, but later scored in the shoot-out that Ghana lost.
“We said to Asamoah that anyone can miss a penalty and it is part of football and it was the only mistake he made,” said Pantsil.
“In fact, it was not a mistake at all. It is part of football and he kicked it from his heart and we all wanted to win the game.
“We have been talking to him. He is feeling bad about that. It is not easy just to forget about something like that.
“He is a young lad and, if he continues to think about it, it is going to affect him.”
“It shows his character that he took our first penalty in the shoot-out,” he added.
“He did well to come back and put another one away in the end. That shows he will very soon forget about it. He has to.”