Large numbers of Magpies supporters departed St James' Park before the end of the match to show their displeasure towards Pardew and owner Mike Ashley.
Newcastle had gone on a run of six consecutive defeats before beating Cardiff, and Pardew insists that he is well aware why fans are not happy with the club's lack of success.
"It is understandable. We had gone so long without winning and they are very frustrated. They want to see us challenging at the top of the league," he told BBC Sport.
"That is difficult with the finances that we have, but we have got the chance in the summer to hopefully to bring in some quality players and try to get into the top five or six.
"We are all frustrated, but I have to take my hat off to the players because the environment was very, very tough for them and they showed tremendous character. It was that depth of character that we needed."
Newcastle's season comes to an end next Sunday when they take on Liverpool at Anfield.