Bodmin Town are through to the last 16 of the FA Vase for the first time in their history.
The South West Peninsula League leaders beat Northern league side Ashington 3-2 at Priory Park.
Glynn Hobbs gave Bodmin a ninth minute lead but Glen Taylor equalised after an hour from the penalty spot.
Steve Colwell put the home side 2-1 up and Adam Carter made it 3-1 on 86 minutes before Matt Grieve got a stoppage time goal for the visitors.
"It's down to the players, they've been fantastic," Bodmin boss Darren Gilbert told BBC Radio Cornwall.
The victory sets up a fifth-round tie at home to either Gornal Athletic or Wisbech Town.
"We always knew it was going to be hard, but we knew with the squad that Darren's put together that we've got 16 or 17 players that'll put in a big shift every week," said captain Steve Simmonds
"We're good enough to go on to the next level," Simmonds added.
"Over the past few seasons I've been here we've let ourselves down in the FA Vase.
"We've gone away, haven't been switched on, but we've learnt over the years that we've got to be more professional.
"Once we got the second and the third we saw the game out and I thought we deserved the win.
"It's one of the biggest priorities for us this season, to set ourselves against other teams from higher standards and to prove that Cornish football is as good as we believe."