Vertonghen struck in the 3-2 win.
"We were 2-0 up, 3-1 up and then 3-2 up and you just want to win the game," the Belgian told the Spurs website. "Then we had to defend, because Paul Scholes was dictating the game. He was amazing. I'm so happy we won here.
"It was a great start for us and for me, it was amazing to score at Old Trafford.
"We had a feeling we could do something here. We have a lot of pace in our team with Jermain, Gareth and Aaron Lennon. That's why we were positive.
"We had a good feeling and from the first moments, we tried to press them and tried to attack. The second half was a different story, but it was an amazing performance."