Neath-Swansea Ospreys are only one win away from the Celtic League title after a comfortable victory over a poor Dragons side at St Helen's.
Ospreys (10) 30
Tries: Mustoe, Spice (2), Durston
Cons: Connor (2)
Pens: Connor (2)
Dragons (0) 0
Richard Mustoe's try after almost 15 minutes was the only attacking move of quality in a subdued first half.
Jason Spice scored two tries in 10 minutes shortly after the break, with Shaun Connor adding a second penalty.
Adrian Durston's injury-time breakaway try brought a bonus point and virtually secures the league title.
Prospects for an open and exciting encounter looked good as Mustoe opened the scoring.
After stealing Dragons ball in their own half, the Ospreys backs combined with some impressive handling down the left before Durston timed his pass perfectly for the winger to race clear.
Connor added the conversion, having earlier opened the scoring with a penalty.
The Dragons enjoyed the majority of possession and territory as the half progressed, but they never once put their hosts under any serious pressure as the quality deteriorated.
They had plenty of opportunity to close the gap as the Ospreys were penalised regularly for offences in the tackle area, but Daniel Griffiths missed three relatively straightforward attempts at goal.
A disjointed opening 40 minutes ended with rather harsh yellow cards for Ospreys prop Andrew Millward and Dragons number eight Rhys Oakley in separate incidents.
The home side came out for the second half with much more purpose, and two quick-fire Spice tries ensured there was no way back for the Dragons.
Captain Barry Williams created the first try as he attracted two defenders with a sharp break from a ruck 10 yards out and found his scrum-half with a neat inside pass.
Spice was celebrating again 10 minutes later when he was in the right place to take a short pass from Mustoe after the winger had picked up a loose ball from an untidy Ospreys scrum.
Connor missed both conversions, but the fly-half was on target with a penalty in between the two tries.
The fourth try arrived with the final play of the match as full-back Durston finished off a slick counter-attacking move which left the Dragons defence floundering.
Connor converted to ensure the Ospreys left with maximum points from their last ever game at St Helen's.
Victory of Edinburgh at the Gnoll next Saturday will wrap up their first Celtic League title.
Ospreys: Durston; Terblanche, Bishop, Seveali'i, Mustoe; Connor, Spice; D Jones, B Williams (capt), Millward, Newman, Bateman, Bater, Tandy, Lloyd.
Replacements: R Hibbard, James, Tait, Bonner-Evans, Pugh, Rees, Morris.
Dragons: Tuipulotu; Wyatt, Brew, Winn, Breeze; Warlow, Baber; Snow, Richards, Anthony, Gough, Sidoli, Ringer, Forster, Oakley.
Replacements: Robertson, Black, Thomas, Charteris, Veater, Griffiths, Bryant.
Referee: Olan Trevor (Ireland)