Two more penalties and a drop goal by Brown were answered by one by Bowen in a half which also saw the Scarlets fly-half sin-binned for a professional foul at the breakdown. Worcester flanker Siaosi Vaili had also been shown yellow by referee Phil Fear for another technical offence minutes earlier.
Worcester then extended their 12-6 interval lead five minutes after the restart through Scotland international wing Ben Hinshelwood. Lively scrum-half Clive Stuart-Smith was held up agonisingly close for the Scarlets before Worcester broke clear to claim their second through French centre Thomas Lombard.
At 24-6 the game seemed up for the Scarlets but they put some credibility on the scoreline with a resurgent final 20 minutes.
First replacement Aisea Havili put away with a neat miss-pass following fine work by Garan Evans, then in injury time Dafydd James burst clear down the left showing the kind of finishing that made him a firm favourite at Stradey and gave the scoreline an air of respectability.
Worcester held on to claim a victory, but Scarlets coach Gareth Jenkins was phlegmatic at the outcome of the match.
"It obviously nice to win these games, but it is more important to find out where you are or where you aren't with a couple of weeks to go before the start of the season," he said. "We were desperate for this game and what we have found out is that our lineout is not what it needs to be.
"They had a lot of the game in the first half with the wind with them and as much as we put a lot of pressure on them in the last 15 or 20 minutes we never controlled the game through the lineouts. It is an area that needs to be addressed over the next week or so.
"There were a lot of plus points. Regan was a major plus, it was nice to see Daf back, I was able to see Hottie Louw and Inoke Afeaki play for the first time and also number of our younger players as well."