Ulster suffered their first defeat in seven outings when losing to Scarlets on Saturday night in Llanelli.
It was a disappointing performance from the Irish Province, although conditions did not make it easy for either team.
The Welsh side made better of those and denied the visitors a losing bonus point with a late penalty.
Scarlets, who had drawn their last two fixtures against Racing Metro and Zebre in the Heineken Cup and the RaboDirect Pro12 respectively, were grateful for George Earle’s try, while three penalties from Aled Thomas and one from Steven Shingler were enough to seal victory.
South Africa fly-half Ruan Pienaar scored all of Ulster’s points as the Irish province suffered their third league defeat of the season.
Scarlets: G Owen; N Reynolds, G Maule, A Warren, J Williams; S Shingler, G Davies; P John (capt), K Myhill, S Lee, J Ball, G Earle, A Shingler, J Turnbull, S Timani
Replacements: D Harris, R Evans, J Adriaanse, J Synman, J Barclay, A Davies, A Thomas, C Knight
Ulster: J Payne (capt); A Trimble, D Cave, C Farrell, M Allen; R Pienaar, P Marshall; C Black, R Herring, J Afoa, L Stevenson, N McComb, R Diack, R Wilson, N Williams
Replacements: N Annett, K McCall, R Lutton, M McComish, S Doyle, J McKinney, R Andrew, D McIlwaine
Referee: Alain Rolland (IRFU)