The Brazilian was withdrawn after 16 minutes but returned to star in the victory at Fulham last Saturday.
"The manager has been great with me, telling me that in all his experience he has never known a player who never had an off-day," said Cacapa.
"I should not really have played against Portsmouth because I was carrying a hamstring injury, but I let my heart rule my head because I did not want to let anybody down.
"Now I can only hope that I have had my off-day for this season and I can help us maintain our current good form. I knew the manager and the rest of the players had confidence in me and I hope I repaid them."