United Rugby Championship
Ospreys (19) 31
Tries: Morgan-Williams 2, Parry, penalty try, Moriarty Cons: Edwards 2
Dragons (7) 14
Tries: Dyer, Tuitavuki Cons: De Beer 2
Ospreys enjoyed a happy homecoming with a bonus-point victory over Dragons at St Helen's.
Mark Jones' side returned to the famous Swansea venue in style, scoring five tries in horrendous conditions in front of 5,592 supporters.
Ospreys led 19-7 at half-time after a double by Reuben Morgan-Williams and an effort by captain Sam Parry.
Dragons scored with the final play of the half through Rio Dyer, but Ospreys' driving line-out secured the win by earning a penalty try and a score for Ross Moriarty.
Anzelo Tuitavuki went over for the visitors' second, but they endured an evening to forget.
Dragons had Rhodri Williams, Tinus de Beer and Aneurin Owen sin-binned and Wales were also given a scare ahead of the Nations Championship.
Dyer did not come out for the second half and lock Ben Carter, who established himself in Steve Tandy's starting line-up last season, went off with a head injury.
Ospreys completed a quickfire double over Dragons having won at Rodney Parade a fortnight earlier.
After a predictably tough start to the season in South Africa, Mark Jones' men have won three on the spin and will try to make it four when they host Cardiff on Saturday, 31 October (19:45 GMT) to finish the first block.
Dragons will expect to react to the disappointment with victory against Zebre in Newport.
After some pre-match pomp, Ospreys started strongly and got their reward when scrum-half Morgan-Williams burrowed over from close range in the sixth minute, Dan Edwards adding the extras.
The visitors did a good job of playing into the wind and had been the better side, but then conceded a scrappy second on the half hour.
Morgan-Williams was the beneficiary of Dragons' failure to fall on the ball after a grubber through by centre Lalakai Foketi.
Ospreys were over for a third time as half-time approached when fly-half Edwards was brave with a penalty touch-finder and the pack muscled over from a five-metre driving line-out for Parry's score.
A 19-0 lead would have represented a good effort for Ospreys with the wind, but Dragons had the final say of the half when, after pressure and penalties, recalled Wales wing Dyer crossed for his first try of the season.
Those seven points were cancelled out almost straight from the restart when Ospreys were awarded a penalty try for a 20-metre line-out drive being stopped illegally, with scrum-half Rhodri Williams sin-binned.
Dragons then suffered the loss of co-captain Carter and, straight after Williams' return, a yellow card for De Beer.
Edwards pinned them into the corner from the resulting penalty and the pack did the rest, back-row forward Moriarty following Parry in scoring against his former side.
Tuitavuki gave Dragons a smidgen of hope when he sniped at a ruck and powered over with quarter of an hour left, but that was soon followed by Owen's yellow card for a head-on-head tackle.
Ospreys' home comforts
After a first block of the season that has seen Ospreys play in Durban, Johannesburg, Tbilisi and Newport, they returned to the famous sporting venue they left in 2005.
They have downsized after leaving the Swansea.com Stadium in 2025 and, while there is a long snagging list and plenty of jobs to be done, this felt like a home.
Like at Bridgend's Brewery Field, their ground for 2025-26, there was a lively atmosphere to make up for the rough edges.
It was Ospreys' first game at St Helen's since moving a game against Benetton during the Covid pandemic in 2020.
Their return meant there were plenty of smiles despite torrential rain, especially from the punter who conquered the conditions to win a new £20,000 bathroom by passing the ball through a hole at half-time.
Ospreys came out firing after the restart to ensure that their first half efforts did not go down the pan on a night to remember for the region as they continue to fight for their existence.
How they lined up
Ospreys: Rogers; Hopkins, Watkin (co-capt), K Williams, Giles; Edwards, Morgan-Williams; G Thomas, Parry (co-capt), Botha, R Davies, Smith, Wright, Deaves, Morris.
Replacements: Daniel, S Thomas, Henry, Sutton, Moriarty, Davies, Creighton, Foketi.
Dragons: Anderson; Dyer, Paea, Owen, Tuitavuki; de Beer, R Williams; Martinez, Dee, Lewis, S Davies, Carter (capt), Langton-Cryer, Beddall, Lewis-Hughes.
Replacements: Burrows, J Morris, Coleman, Screech, Minto, Hope, J Lloyd, Inisi.
Yellow cards: R Williams 41, De Beer 54, Owen 67.
Referee: Ben Whitehouse (Wales).
Assistant referees: Craig Evans & Ben Breakspear (Wales).
TMO: Adam Jones (Wales).