Vertonghen was making his full debut for Spurs and conceded that a draw was hard to take at the end of the game.
"It was our first game at home this season and we really wanted to win, so it's painful we drew the game," Vertonghen told the Spurs official website.
"We created a few good chances in the first half for myself, Jermain Defoe, Aaron Lennon and once we scored we really wanted to keep the three points.
"But West Brom had the energy to press us and in the end scored in the 91st minute. As I said, that was painful."
Next up for Spurs is the visit of Norwich City to North London on Saturday.