Despite leading thanks to a Matt Etherington goal in the 29th minute, the Potters allowed the Tigers back in the contest and eventually went down when Seyi Olofinjana levelled then Jan Vennegoor of Hesselink scored a late winner.
Pulis said Stoke were well below par and rued the fact they could not go on with the job after hitting the lead.
"We're disappointed," he said.
"It is the third time we have led away from home this year and not won the game.
"We weren't at our best - but when Matty scored we were hoping that would take us on."
The loss, only their second away from home, left Stoke in 9th position on the league table.