Pardew said that his side should have put the game out of sight but they were undone by two "bad goals".
"That was a tough defeat for us," BBC Sport quotes Pardew as saying. "In the first half we played well and the game should have been out of sight but second half we couldn't get going and unfortunately we have conceded two bad goals.
"Perhaps because we have not won for a while, the pressure was on us. We weren't used to it, we were tentative and it put us on the back foot. We should have gone on. We need to strengthen the squad no doubt about it."
The result leaves Newcastle just two points above the relegation zone.