The result saw Porto bow out of the Champions League, but Casillas appreciated the welcome he received from the Anfield crowd. It could mark the Spaniard's last appearance in the competition.
The Real Madrid legend said: "This is a field that respects the players and I am grateful that the fans applaud the players, when I came here with Real it was the same."
On his recall, Casillas continued: "All players are always trying to change the opinion of the coach, not only Iker Casillas, but also the rest of the squad.
"We have to work for the mister to choose us. In this sense, we all work to be able to play. We are out of the Champions League today, but we are leaders in Portugal and we have to defend that."