The hosts saw off their Welsh regional rivals by five tries to one with skipper Ryan Jones, Dan Biggar, who scored 22 points, Nikki Walker and Ryan Bevington adding to a first-half penalty try.
The Ospreys led 16-3 at the break – Biggar knocking over three penalties and a conversion, while opposite number Jason Tovey kicked a single penalty.
And they had to wait until nine minutes into the second half for their next try, when Ryan Jones went in for a pushover score.
A poor line-out from the Ospreys allowed the Dragons to pounce for their only try, which was scored by scrum-half Wayne Evans.
And with prop Aaron Coundley in the sin-bin for continual collapsing of the scrum the Ospreys scored three more tries through Biggar, who finished off an impressive counter attack, and Walker and replacement prop Bevington.
Ospreys scorers: Tries: Penalty, R. Jones, Biggar, Walker, Bevington. Cons: Biggar 4. Pens: Biggar 3.
Dragons scorers: Tries: W. Evans. Cons: Tovey. Pens: Tovey.
OSPREYS: Byrne, Bowe, Bishop, Hook, Williams, Biggar, M. Phillips, James, Bennett, A Jones, A Jones, J Thomas, Collins, Holah, R Jones.
Replacements: Walker for Bishop (66), Nutbrown for M Phillips (73), Shervington for Bennett (73), Bevington for A. Jones (65), Gough for A Jones (65), Tiatia for R Jones (65).
NEWPORT-GWENT D’GONS: Harries, Hughes, Gomer-Davies, Leach, Fussell, Tovey, W. Evans, Coundley, Willis, Castle, Sidoli, MacDonald, Coombs, Harris, L Evans.
Replacements: Riley for Leach (66), Greendale for W. Evans (73), Palmer for Castle (50), Groves for MacDonald (66), Burns for L. Evans (41).
Referee: Nigel Owens (WRFU).