The Scarlets scored three tries through Tavis Knoyle, Andy Fenby and Rhys Priestland who also slotted two penalties and two conversions.
The victory puts the Scarlets just four points behind Newport Gwent Dragons in the race for the highly prized Heineken Cup spot but Paul Turner’s side will be hoping to put some distance between themselves and the Scarlets along with the Blues, when they host Munster tomorrow.
Early tries from Fenby and man-of-the-match Knoyle gave the home side a 15-3 lead at the break. Paddy Wallace gave Ulster hope with an early second half try, but David Pollock was sin-binned along with Ryan Caldwell which meant the Irish side were on their way to their first defeat since 26 December 2009.
Wing Joe Ajuwa set up the Scarlets first try with a powerful burst. As a result fellow wing Fenby scored in the corner with ease.
David Lyons burst from a scrum to off-load to Knoyle who evaded the Ulster defence to scoot over out wide.
Humphreys banged over a long range penalty with the last kick of the first half to give Ulster hope but despite scoring early in the second half, the Scarlets were always in control as they went on to record their first league victory since New Year’s Eve.
