Ulster captain Rob Herring admits a long three weeks lie ahead after a poor performance condemned the province to their first defeat in the Guinness Pro12.
Scarlets claimed a victory despite playing half an hour a man light after prop Peter Edwards, skipper John Barclay and replacement lock George Earle all received yellow cards, but the hosts were able to keep the visitors at bay after building a 16-0 lead through the boot of fly-half Dan Jones and a try from wing Hadleigh Parkes.
The display infuriated Ulster head coach Neil Doak, with hooker Herring handed post-match media duties while the former scrum-half simmered down ahead of a three-week wait to make amends as the Pro12 schedule takes a break while the World Cup kicks off.
"We are not happy, but we have to regroup, we have a few weeks to get it right," said Herring.
"There is some anger there. There have been some harsh words in the dressing room."
Ulster had briefly threatened to salvage a draw as the yellow cards took their toll on the Welsh side. Wing Rory Scholes held off two tackles to dot down in the corner, while a penalty try from an organised rolling maul had them back within seven points with seven minutes to play.
But it was not to be as the Scarlets controlled possession and replacement Aled Thomas sealed the win with a late penalty.
Scarlets- Evans; Williams (Nicholas 79), King, Owen, Parkes; Jones (Thomas 79), A Davies; John (Evans 58), Phillips (Myhill 79), Edwards, Price (Taylor 39- 48), Rawlins (Earle 52), Shingler, J Davies, Barclay (Pitman 75).
Ulster - Ludik; Gilroy, L Marshall, McCloskey, Scholes (Arnold 79); Nelson, P Marshall; Warwick (Black 58), Herring, Herbst (Lutton 67), Browne (Diack 58), Van der Merwe, Wilson (Ross 58), Faloon, Williams.
Ref - A Brace (IRFU)