Loic Remy twice gave his side the lead in the first half, but Robbie Brady and Ahmed Elmohamady struck equalisers to keep Steve Bruce's side in the game before Sone Aluko hit a superb winner from the edge of the box with 14 minutes left.
Newcastle had come into the game off the back of two league wins in their previous two matches, leaving Pardew puzzled as to why they could not hold on for the three points against a newly promoted Hull side.
"We weren't tight enough as a team, we were loose today and Hull exploited those spaces," said the Newcastle boss.
"It's the consistency of performance that this team is searching for.
"The team that finished fifth, you can see similarities in this team, but that team had a consistency in performance as a team, not as individuals.
"Today the formation was the same, the set-up was the same but we looked not the same.
"We were too loose and gifted them goals and you can’t do that against any opposition and Hull, I'll be the first to pay tribute to them because they played very well, but for us it is a really disappointing day."
