Early goals from Christian Eriksen and Harry Kane gave Mauricio Pochettino's side a commanding first-half lead before Kane sealed his brace, and the points, with a second-half penalty.
Pulis felt his side had not done enough to push the visitors back in the opening stages.
"The first 20 minutes was poor because we started sloppily and gave the ball away to them too many times," he said.
"We didn't play with any tempo and you have to do that at home because you need the support behind you.
"But we've got to try and bounce back and make sure when we're at home we play at a tempo, and after the first 20 minutes I think we did play with a tempo."
Tottenham, now well-placed in the hunt for UEFA Champions League football, were two up inside the opening 15 minutes thanks to Eriksen's sublime free-kick and a thunderous strike from Kane.
Hugo Lloris did well to keep out efforts from James Morrison and Claudio Yacob as Albion responded, while Craig Dawson's header cannoned off the crossbar.
"I don't think it's a 3-0 game, and we can play better and we have to play better," added Pulis.
"We gave them a two-goal lead after 20 minutes so then we needed a goal, and to be fair their goalkeeper [Lloris] was absolutely fantastic – he's made some really wonderful saves.
"In the second half we had some good chances, but then they got the penalty and then that killed it."
