Ospreys 48 Ulster 17: The Ospreys shrugged off controversial star Gavin Henson's absence to claim an important bonus point victory in their quest for a Heineken Cup quarter-final place.
Henson courted all the pre-match headlines, but his team-mates were not distracted as they destroyed the 1999 European champions.
Henson broke a bone in his hand during the EDF Energy Cup victory over Harlequins last weekend that will sideline him until mid-January.
But he was also involved in alleged rowdy behaviour with three friends on a train home after the game, although Ospreys officials insist the injury happened during a hard-fought 19-8 win.
But while Henson contemplates another spell on the sidelines, early tries from centre Sonny Parker and scrum-half Justin Marshall meant there was danger of Ospreys going off the rails.
Ulster, whose coach Mark McCall left his post following a thumping home defeat to Gloucester last month, suffered their third successive Pool Three loss.
Caretaker boss Steve Williams, a former Wales international, would have gained satisfaction from some spirited defence, but Ulster were starved of possession and could offer little in attack, apart from touchdowns by Isaac Boss and Simon Danielli.
It was game, set and match inside 50 minutes as further tries by lock Alun-Wyn Jones and skipper Filo Tiatia guaranteed the Ospreys' maximum points to stay in touch with group pace-setters Gloucester.
Wing Nikki Walker added a fifth touchdown before full-back Lee Byrne and Walker again completed Ulster's misery, with fly-half James Hook booting five conversions and a penalty.
The teams meet again in Belfast next Friday night, when Ospreys coach Lyn Jones will demand a repeat performance after seeing his side post their biggest Heineken Cup win.
But Ulster's European campaign is all over bar the shouting, leaving them lurching towards a pool stage exit for the ninth successive season.
The Ospreys desperately needed victory after coming unstuck at Gloucester last time out, and they went into battle as red-hot favourites, parading a team of 15 internationals.
Hook took the fly-half role Henson filled against Quins, while Ulster were without injured number eight Roger Wilson, which meant lock Matt McCullough switching to back-row duties.
Ospreys blasted out of the blocks, taking a fifth-minute lead when full-back Lee Byrne's beautifully-timed run enabled him to send Parker over wide out.
And they should have scored again just three minutes later, but wing Shane Williams' brilliant 50-metre break did not gain the reward it deserved after he was tackled and his unmarked support runners got their angles wrong.
Ospreys though, bagged a second try inside the opening quarter following sustained pressure that saw Ulster inevitably run out of defensive numbers and Marshall crossed unopposed.
Fly-half Paddy Wallace reduced Ulster's deficit by slotting an angled penalty, and the Ospreys could make no further inroads before the break.
The second period was all about Ospreys going in pursuit of a bonus point, but once it arrived they didn't take their foot off the pedal.
Only some committed tackling kept out a hungry back division, although Ulster were powerless to stop Walker and Byrne completing a six-try Ospreys performance.
The victory surpassed their previous biggest Heineken Cup win of 46-19 against Harlequins in 2004, and flashed a warning signal to Gloucester — impressive bonus point victors over Bourgoin in France tonight — that the group outcome is not a foregone conclusion.
