Stephen Ferris went over twice as Ulster came back from a early bombardment to claim much-needed Pro 12 League points at Ravenhill last night.
Man-of-the-match Ferris had steamrolled the Welshmen all night and his double helped calm Ulster nerves, which had been shredded after tries from Sean Lamont and Viliami Iongi early in the game.
After turning around 10-8 in arrears, Ulster scored 16 points without reply, aided by the boot of Ian Humphreys, who contributed four penalties and a conversion for a useful evening's work.
Ulster should have closed out the game there and then, but when they were reduced to 14 men with nine minutes remaining they had to hang on after Kevin Murphy touched down to leave a converted try between the sides.
It was catastrophic start for Ulster when -- after a Scarlets hand had not touched the ball from the kick-off -- Pedrie Wannenburg had a soft pass easily picked off by Lamont, who casually crossed in the corner from 22 metres out.
Ulster had showed their intentions of wanting to keep the ball in hand against a very stiff breeze but they were finding possession hard to come by.
It was the Scarlets who forced turnovers as Ulster's error count rose and it was no surprise that the visitors nudged further ahead in the 18th minute.
It was the pack who moved effortlessly into the Ulster '22' and when they ball was swung wide right, Fijian wing Iongi swerved inside Craig Gilroy's tackle and charged over out wide.
Humphreys narrowed the gap three minutes later with a penalty, but it failed to inspire Ulster. However, after the Scarlets were reduced to 14 men when full-back Daniel Evans was sent to the bin, Paul Marshall sparked the revival when he took off down the blindside of a ruck on the halfway line and followed his kick ahead to take Ulster to the opposition '22'. With the Scarlets in disarray, the ball was moved left for Ferris to dive over.
The Scarlets were left defending a narrow two-point lead into the wind on the restart but that was immediately negated with a second Humphreys penalty from close-in.
An Ulster try went abegging soon after when Darren Cave made a burst through the middle with the Scarlets' defence all over the place but Rory Best's pass found a black jersey instead of white. All they got was another Humphreys' penalty to ease 14-10 ahead.
The game then lost whatever structure it had for a period, with neither side really stamping their authority before Humphreys' fourth penalty put a little daylight between the sides.
Ferris then grabbed his second try of the match when, from a line-out, the ball was whizzed across the three-quarter line and Cave delivered an exquisite pass in front of the flanker, who took the ball at high speed to charge over Lamont and sidestep Evans for a classic try, which Humphreys converted.
With 10 minutes remaining, Ulster coach Brian McLaughlin emptied his bench but unfortunately prop Adam Macklin was only the park for 30 seconds before he was yellow-carded for a ruck offence.
That almost proved disastrous as the Scarlets immediately had Ulster in reverse and No 8 Murphy slipped through Ferris' tackle to score at the posts.
But a nervous Ulster held on to claim a much-need victory ahead of next week's visit of Aironi.
Ulster -- A D'Arcy; A Trimble, D Cave, N Spence (Whitten 60), C Gilroy; I Humphreys (Jackson 70), P Marshall (Pienaar, 63); T Court (McAllister 54), R Best (Brady 70), J Afoa (Macklin 70), J Muller (capt), D Tuohy (Stevenson 54), S Ferris, C Henry (Diack 70), P Wannenburg;
Scarlets -- D Evans (Newton 65); V Iongi, N Reynolds (I Evans 38; Williams 55)), A Warren, S Lamont; S Jones (capt), G Davies; P John (Thomas 58), K Owens (Phillips 55), D Manu (Gardiner 66), L Reed, A Powell, (Welch 55), M Gilbert (Edwards 48), R McCusker, K Murphy.
Ref -- A Rolland (IRFU).