The scoreline was 1-1 at half-time and the hosts had proven to be tough opponents, but the Spireites scored twice in the second-half to deservedly take home the points.
Penn said: “Credit to them, credit to the manager, they came here as a proper top of the league outfit, with a top of the league atmosphere, with some top, top players. They have done a job so fair play to them. We wish them all the best in their quest for promotion.
"We have watched their last five games and they have beaten teams four and five-nils. We conceded a really soft first goal when I thought we were on top. I thought we created some really good chances in the first-half and we were solid and well worthy of going in 1-1 at half-time.
“And then I think their quality shone through. We showed lots of endeavour and we put our bodies on the line but that extra bit of quality has won them the game today. They are a good team and our season is not going to be defined by this result. But, on the flip side, I am still disappointed we have lost the game.
"They moved the ball about really well – it doesn’t help when you go down to 10-men against these teams, and that has hurt us, that lack of discipline.”
He added: "I think that is the best we have played in a long time, especially that first 45. We had a right go today. I can’t be any prouder of the lads, I thought they gave us everything.”