Goals from Adam Lallana and Gaston Ramirez saw off Pardew's men, who have won just one of their last eight league encounters ahead of a midweek trip to Stoke.
"We're worried, of course we're worried, because we are Newcastle United and we've really got that dressing room to take into Wednesday night," said Pardew.
"It's not like we can add four or five players from the squad into that group. That is our group and they have been soundly beaten today and are going to another tough place.
"We have three days to try and lift the team to try and get ready for another tough game.
"I thought it was all good up until when it kicked off. It was nice to see some old friends and nice for the fans to give us a nice ovation but obviously it stopped when they got amongst us.
"They did a good job today and we were unlucky as they had a great result at QPR and their tails were up. Their confidence was there and that made it even more difficult for us."