WING George North was stretchered off with a neck injury as the Scarlets suffered another damaging blow to their Pro12 play-off ambitions at Ravenhill last night.
Just a month out from the start of the Six Nations, North threw a huge scare into the Wales camp when he suffered the knock midway through the second half.
It compounded another tough night for the West Wales region who came up against an Ulster side in outstanding form.
Spearheaded by South African scrum-half Ruan Pienaar and rampaging No. 8 Nick Williams, the league leaders ran in five second-half tries to cement their position at the top of the table.
And even though they battled hard throughout, the Scarlets must again bounce back from another heavy defeat following their hammering at the hands of the Ospreys on Boxing Day.
The defeat at the Liberty had been damaging not just on the scoreboard, with 12 players absent for the trip to Belfast.
Among those ruled out were Aaron Shingler, Liam Williams, George Earle and hooker Matthew Rees, while centre Gareth Owen sat out the first week of his three-week suspension.
Ulster, in contrast, were able to bring back the big guns following their first league defeat of the season against Munster, and one of those was Springbok star Pienaar, who was making his 50th appearance for the province.
It was the Scarlets who took the lead on eight minutes through an Aled Thomas penalty, but the fly-half then pulled another chance to double the visitors' advantage.
With skipper Rob McCusker to the fore, the Scarlets enjoyed the better of territory and possession in the opening quarter, but Ulster were level on 21 minutes thanks to a long-range strike from Pienaar.
A brilliant midfield break from Wales centre Jonathan Davies provided further evidence of the Scarlets' threat in a see-sawing contest that was proving a great advert for the Pro12.
But it was Ulster, thanks to a thunderous charge from No. 8 Nick Williams and the boot of Pienaar, who took the lead with a second penalty, before the South African added another to make it 9-3 at half-time.
The Scarlets needed to respond strongly at the start of the second half, but it was Ulster who were over for the game's first try just three minutes after the restart.
It was a fine effort from the side — Williams punched the initial hole and after a superb off-load, good hands from hooker Rob Herring put flanker Robbie Diack between the posts.
Pienaar's conversion made it 16-3 and when he added a penalty shortly after, the Scarlets were staring down the barrel of a fifth defeat in six matches.
Another rampaging run from Williams almost brought a second converted try for the home side, but the Kiwi wasn't to be denied when he ploughed over from short range.
The Scarlets would have been delighted to have seen the back of the destructive Williams when he was replaced just before the hour mark, but such is the strength of Ulster's squad that they were able to bring on the experience Roger Williams in his place.
Matters got worse for the Scarlets when Wales wing George North was stretchered off, but they were rewarded for their efforts when flanker Josh Turnbull hit a great angle to cross after a sizzling counter-attack from Kristian Phillips.
But it was a brief respite for Simon Easterby's side as a try from wing Andrew Trimble, a penalty try, which saw Aled Thomas sin-binned, and a last-minute effort from replacement Neil McComb gave Ulster an emphatic bonus-point win, despite a last-minute try from replacement Scott Williams.