The Spartans ended Stockport County's 12 game unbeaten run on Tuesday night and Armstrong admitted the result was more than they had hoped for.
"It was a real battling performance there and the quality was the most pleasing thing," he told the club's YouTube service.
"We could’ve probably had a couple more with a little bit more composure but they [Stockport County] are a good side, I would’ve taken the draw before the game but to get all three makes me delighted with the lads.
"This week we probably caught them at the right time to be honest with you. They’ve had to travel to us midweek and then they’ve got Chorley on Saturday and then the FA Cup after that.
"We had to match them up better than we did against Curzon Ashton on Saturday. We had to nullify their threat and I thought we did that.
"Our best form of defence is attack because of what we’ve got. Even our full backs are attack minded, so we’ve got to play to our strengths.
"I can’t just keep telling the lads we’ve got to sit back and defend because we’ve got to get at teams. If we don’t, we end up dropping off far too deep and inviting pressure."
Next up for Armstrong's men is Saturday’s FA Trophy Third Qualifying Round home tie against Marske United.