Son was on target as we fought back from 2-0 down to level in the second half.
But we then lost Kieran Trippier on 73 minutes and with three substitutes on, we were down to 10 men.
Momentum shifted back in Wycombe's favour and Garry Thompson headed them into a 3-2 lead with seven minutes left on the clock.
Below: Sonny speaks to Spurs TV
"I knew we wouldn’t give up because we had five minutes where we could score," said Sonny. "That was my feeling. I wasn’t thinking about losing this game. I had that feeling...never give up."
Dele Alli levelled at 3-3 on 89 minutes before Sonny provided the thrilling finale, a one-two with Vincent and slotting home the winner in the seventh minute of injury time.
"I still believed we could do it," he added. "I felt we could win the game.
"It (the winner) was a special moment for me and the fans. It’s something crazy. It’s great to have fans like this and I’m happy for them. The celebration was for them."
Just before starting his interview with Spurs TV, Sonny said: "Winning is always good."
"Yes, this is true," he added. "And to win, we had to work really hard."