Albion controlled large periods of the game at the Tottenham Hotspur Stadium and restricted Spurs to zero shots on target.
With the game heading for a goalless draw, Trossard took advantage of a mix-up at the back and brilliantly placed the ball past Hugo Lloris on the 89th minute.
He said: “I’m really happy for myself and especially for the team. It was a really good game.
“We kept on going and we reduced their chances. It was the perfect game for us.”
The Belgium international was deployed at wing-back as Graham Potter tweaked the side which beat Arsenal 2-1 last weekend.
“He (Potter) said yesterday that he had a special role for me at wing back,” Trossard said.
“He knew that I did that at Belgium.
“I think it worked well.
“That’s one of my strengths that I can play almost anywhere, except maybe centre back.
“I always do my best to help the team.”
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