Ospreys (21) 49
Ospreys centre Sonny Parker scored two tries at a crucial time
Tries: S. Williams, B. Williams, Parker (2), Marshall, Henson
Cons: Henson (5)
Pens: Henson (3)
Gloucester (6) 19
Pens: Mercier (4)
The Ospreys scored six tries against a weakened Gloucester side to clinch a bonus-point win in the EDF Energy Cup.
Shane Williams set the tone with a try after a minute, and a Barry Williams try and four Gavin Henson kicks gave the home side a 21-6 half-time lead.
Sonny Parker crossed for two quick-fire tries after the break, with Marshall and Henson also touching down.
Gloucester were limited to four Ludovic Mercier penalties before Peter Richards pounced on a loose ball to score.
The Ospreys players had promised to "stand up and deliver" after their crushing defeat to Ulster last weekend, and they were certainly true to their words as they looked back to their attacking best.
Their superiority in the backs was immediately evident as Shane Williams gave them the perfect start after exactly 60 seconds.
A scrum near the Gloucester 22 supplied the perfect platform and the visitors had no answer to quick midfield offloads which created an overlap for wing Williams to cross in the right corner.
The second try 12 minutes later was a far simpler affair as hooker Barry Williams dived over from a textbook catch and drive from a close-range lineout.
Henson added the conversion, and landed three penalties before the interval to give the Ospreys a healthy lead.
The second penalty followed a yellow card for Gloucester winger Mark Foster, who was penalised for preventing the Ospreys from taking a quick lineout.
Gloucester, showing seven changes from the side that beat Northampton in the Guinness Premiership last weekend, struck first after the break with Mercier's third penalty.
But the Ospreys replied with two Parker tries in five minutes which put to rest any fears of a Gloucester fight-back.
Henson started the first with a blind-side move just inside opposition territory which saw Parker time his run perfectly to take a short pass and score in the left corner.
Parker had played a prominent part earlier on in the move and got away with a blatant forward pass.
But the centre's second score was all his own doing as he touched down in virtually the same spot after slicing through the Gloucester defence from a midfield scissor move.
Henson converted both to take the home side clear at 35-9.
A rare piece of attacking play from Gloucester - unbeaten in the Premiership this season - brought a try for replacement scrum-half Richards, which Mercier converted to maintain his perfect record.
The try-fest continued with another Ospreys double-whammy as Marshall - who had a try disallowed in the first-half - and Henson crossed under the posts in the space of three minutes with over 20 minutes still to go.
Henson, who added the easy extras, looked back to his best as he ran the show at fly-half and his wonderful solo try brought a broad smile to his face.
The only worrying note for the Ospreys was a knee injury to Ryan Jones which forced the number eight off the field midway through the second half.
Ospreys coach Lyn Jones:
"It was a powerful performance by us. The fellas have responded well from last week and trained well.
"I keep saying it takes time to develop a side, and we looked like one tonight.
"We created space and you could see individual flair coming through. I'm just delighted for everybody."
Gloucester coach Dean Ryan:
"Intensity was the core area. They won the physical collisions and played off the back of that with a world-class number nine (Justin Marshall).
"We didn't turn up with enough intensity to make it an even contest, which was disappointing.
"Coming to this type of environment, you will receive an extremely physical game, and it was a great opportunity for some people to learn some lessons."
Ospreys: Byrne; Walker, Parker, A. Bishop, S. Williams; Henson, Marshall; D. Jones (capt), B. Williams, James, Cockbain, Evans, A. Wyn Jones, Tandy, R. Jones.
Replacements: Connor for Byrne (74), Selley for Parker (74), Spice for Marshall (74), Shervington for B. Williams (74), A. Wyn Jones for James (51), Bateman for Cockbain (76), Thomas for Tandy (59).
Gloucester: Morgan; Bailey, Adams, Allen, Foster; Mercier, Lawson; Collazo, M. Davies, Forster, James, Eustace, Balding, Boer (capt), Narraway.
Replacements: Thirlby for Morgan (71), B. Davies for Mercier (73), Richards for Lawson (55), Wood for Collazo (59), Azam for M. Davies (48), Merriman for Balding (54).
Not Used: Bortolami.
Sin Bin: Foster (39).
Ref: Hugh Watkins (Wales).