The Magpies suffered their heaviest defeat of the season at St James' Park on Saturday to drag themselves back into the relegation battle.
"There were poor goals and defensively we were not good enough today," Pardew told BBC Sport.
"We really didn't do ourselves justice, we lost a little bit of fight and a bit of heart and it turned into a terrible scoreline for us.
"Perhaps we need a bit more experience on the field and I will look at that in the selection next week."
Newcastle, who are five points from safety with three games remaining, continue their campaign next Saturday with a trip to West Ham United.