The first leg of their last 32 clash ended goalless, leaving the tie well balanced for when the teams meet again next week.
Papiss Cisse was denied twice - once in each half - although TV replays show that Senegalese striker may well have onside for both.
A disappointed Pardew said: "Both 'goals' were goals. When you see the replays, you can see that.
"The first one, I have to say, I was a little bit undecided from where I stood, but the second one I thought was a definite goal.
"It's tough to take because in these games, those margins are the difference.
"He (Cisse) could have two goals to his name as well if the decisions had gone his way.
"When you get decisions like that going against you, it puts fire in your belly.
"We came off the pitch very, very disappointed with those decisions and we are going to take that into the second leg."