The Baggies earned their first win of the season, but Spurs were poor all afternoon and Mauricio Pochettino's side are now without a win in four in all competitions.
Younes Kaboul, who was recently appointed as the first-team captain, has criticised the team's display and is hoping to see an improved performance against Nottingham Forest in the Capital One Cup on Wednesday night.
"We're all disappointed, of course, after this poor defeat, I think we played with a slow tempo all of the game and we never looked dangerous, or a threat for West Brom.
"They took their chances and they scored from a corner. It was not good enough from us. I am still questioning everything, what went wrong. We didn't create any chances.
"We were just inviting them to try to score. It was not good enough from us. But that's football and we have to go back to training with a better mentality also.
"It is a tough week, every game is tough. The game on Wednesday is important for us because we want to win something this season.
"Forest are a good side, they are doing well in the Championship and we have to bounce back straight away on Wednesday," Kaboul said.
The 28-year-old partnered Vlad Chiriches at the back, but the Spurs duo struggled to contain West Brom on the break as Saido Berahino and Stephane Sessegnon caused all kinds of problems.
James Morrison's header sealed the victory in the second-half and Tottenham must improve for Wednesday's game against Forest.
The Championship side have started the new season under Stuart Pearce in great form and have yet to lose a game in eight.