Wolves won 2-0 thanks to second-half goals from Joao Gomes and Rodrigo Gomes.
Armstrong, who joined Wolves in January from Southampton, said: "It has been brilliant coming into this side.
"I knew the circumstances before I came in and I can't thank the team enough for the praise that I have been given.
"Performances like that are why we play football. We know where we are in the league but a game like that in a derby, it is massive."
On creating Joao Gomes' goal, Armstrong also said: "It was a pass from me! I took a touch down and luckily Gomes was there to finish it off. We knew we would get chances and the boys were outstanding in the second half too."
On manager Rob Edwards, he added: "He is brilliant and we work hard as a team. A night like tonight is amazing."