After a first half stalemate, an incredible second half saw Garforth fall behind to Ashington in the fifty third minute, before Luke Aldrich restored parity with a goal three minutes later.
Jordan Emery put the Miners into the lead on seventy nine minutes, with Dan Coupland extending the winning marging with four minutes left on the clock.
Second half sub Mutty put the icing on the cake with a stoppage time finish.
Garforth have two home games in the coming week, starting with a County Cup second round tie against Ossett United on Tuesday (7.45pm kick off), followed by an NPL East match against against Blyth Town next Saturday (3pm kick off).