The Black Stars surrendered a two-goal lead before suffering a 4-2 loss to Gambia at the Accra Sports Stadium on Tuesday, leaving Mensah concerned about the team's ability to maintain intensity during matches.
Mensah admitted that the players had fallen short but said the experience should provide important lessons for the squad, particularly those making their first appearances for Ghana.
"There is some urgency and some spirit we need to have when we play for Ghana," Mensah said, as quoted by Modern Ghana.
"In the end, we have a whole lot to learn."
The skipper believes the difference between playing for a club and representing Ghana was evident during the collapse against The Gambia.
"Playing for Ghana, where everybody lives off football, is completely different from club football," he said.
"Everybody is happy when Ghana wins a game. I think that was the part we were missing."
The captain highlighted Ghana's reaction after scoring their second goal, claiming the players failed to maintain the necessary focus and intensity.
He also accepted responsibility for the result and said the senior members of the squad had to shield the younger players from the criticism that followed the defeat.
"As captain, I also take responsibility for everything that happened on the field," he said.
"We have to protect the boys and protect the national team. We can take the criticism and everything that is supposed to come to us."
Mensah also defended the players who accepted their call-ups despite the challenges facing the squad, pointing out that some experienced players were unavailable because of injuries and he believes Ghana can still use their remaining qualifiers to rebuild confidence and reconnect with supporters.
"At some point we should also appreciate them. As captain, I am proud of them for not hiding and for coming out to play for Ghana," he added.
"We have the chance to do it again and to make people happy again."