"We're all disappointed, of course, after this poor defeat," Kaboul told the club's official website. "I think we played with a slow tempo all of the game and we never looked dangerous, a threat for West Brom.
"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."
Tottenham have the chance to get back to winning ways on Wednesday when they host Nottingham Forest in the third round of the League Cup.