Returning Springboks Damian Willemse and Sacha Feinberg-Mngomezulu made an immediate impact as the visitors dominated territory, possession, and the set piece to record their fifth consecutive victory over the Welsh side.
The Stormers started with clear intent, controlling the scrums and forcing the home side into repeated infringements. After missing an early penalty attempt, Feinberg-Mngomezulu helped his side open the scoring when No. 8 Evan Roos powered over from close range in the 11th minute. The flyhalf added the conversion for a 7-0 lead.
Feinberg-Mngomezulu kept the scoreboard ticking with a penalty soon after, before Paul de Villiers crashed over from a well-worked lineout to give the Stormers a 17â-0 halftime advantage. Even a yellow card to flanker Ben-Jason Dixon did little to halt the South Africans' momentum, as their scrum superiority and defensive organisation kept the Scarlets scoreless.
The Scarlets showed more energy after the break, enjoying brief spells of possession inside the Stormers' half, but were repeatedly repelled by fierce tackling from the visiting forwards. The Stormers' pack soon reasserted control, with Ruben van Heerden barging over for the team's third try in the 57th minute, converted by Willemse.
Any hopes of a Scarlets comeback were extinguished when Feinberg-Mngomezulu returned from a yellow card to pick up a loose ball and score in the corner, extending the lead to 29-0. Replacement scrumhalf Imad Khan added the finishing touch in the 75th minute, darting over from the base of a dominant scrum to seal a bonus-point victory.
For the Cape side, the result marked their third win in as many matches to move back to the top of table - for the time being at least - while the Scarlets' struggles continue as they remain rooted to the bottom of the standings.