The need for strong character and a better fighting spirit was a priority now with qualification for the 2014 World Cup in Brazil starting in less than six months.
"We achieved a good level in the qualifiers to get to the Nations Cup, maybe too good a level and we were persuaded we could achieve something at the tournament," Gerets told reporters.
"We discovered that in this competition you not only have to be physically strong but you also need to have character.
"You've got to keep playing your football. It seems to me you have to have a mentality to want to impose yourself on the game. I regret that we did not have sufficient character."
"We were shaken up. We were not as ready for the tournament as we thought we were," said Gerets, a former Belgium defender who competed at three World Cups.
"For many of my players, this was their first Nations Cup and now they have time to analyse themselves and what they did here."
"I'll take some of them aside and we'll have a good talk," he said.
The coach's future is also under a cloud but he hinted his job was safe. Last week after the defeat by Gabon he said he wanted to stay on and he repeated that as he departed.
"I'm not going to flee, I'm going to be working with everyone in this team. This [experience] will help us to become a stronger team," he said.
"If you had asked me before the tournament whether I thought we could qualify for Brazil, the answer would have been 'yes' but now we'll have to wait and see how the players bounce back," Gerets said.
