Live on the BBC, the National League Lambs had one of their greatest ever days as they upset the Terriers, playing Premier League football just six years ago.
Tom Tonks’ long throw caused chaos and Chris Maxwell got the final touch for the all important goal late on in the first half.
There are 57 places between part time Tamworth and the League One side but the favourites couldn’t find a way past the steady Jas Singh and the headlines were written.
“I said I just wanted to be competitive and not disgrace ourselves on national TV and we certainly didn’t,” manager Andy Peaks said.
“I’m proud of them. I thought we managed the game very well. We were really good.
“We knew we had to keep the ball, work hard and keep our shape and we knew we would be good from set pieces.”
It wasn’t to be for Alfreton in the night’s other game, going down 5-1 at Notts County despite taking the lead through Liam Waldock.