The Black and Ambers were chasing a league double having won the first exchange between the two sides earlier in the season and they looked on course, going into a 24-18 lead.
But Newport were left stunned as two stoppage-time tries by winger Matthew Nuthall and No 8 Dan Godfrey confirmed Ponty’s place at the top of the points table.
Despite putting in a plucky performance where Newport’s pack put in a solid shift, the visitors came away with nothing while the hosts picked up a bonus point with their four tries.
Pontypridd scorers: Tries: C Dicomidis, W O’ Connor, M Nuthall, D Godfrey; Cons: D Flanagan (3); Pens: D Flanagan (2)
Newport scorers: Tries: D Robinson, R Downes; Con: T Hancock; Pens: T Hancock (4)