Cristiano Ronaldo scored two goals while Dimitar Berbatov, Michael Carrick and Danny Welbeck scored one each.
“The game plan was to keep things as tight as we could but we conceded after a couple of minutes,” Pulis told Sky Sports.
“I thought we did OK after that, but they scored in first-half injury time and that kills you.
“They then scored just after half-time and could smell blood after that. They played some smashing football.
“We are disappointed because we conceded poor goals at poor times during the game.”
“We managed to beat Arsenal and got something against Liverpool but it wasn’t to be today,” he added.
“We’ve just got to wash this away now and move on to the next game.”