RYANConbeer crossed for two first-half tries in Galway as Scarlets won back-to-back games for the first time this season and climbed to second place in Conference B.
Glenn Delaney's side added to their interval lead when Dane Blacker scored their third try three minutes after the break, and with Connacht unable to claim their chances they held on for the win in driving rain.
Connacht, who've had their last two games postponed due to Covid-19 outbreaks in their opponents' camps, looked rusty in the first-half, and will feel this was a missed chance against their group rivals.
Playing with a strong Sportsground wind at their back, Scarlets gained early territorial advantage, and after a couple of early looks the Welsh outfit took the lead after six minutes. A driving lineout on the left was well halted by Connacht's maul defence, but when Dan Jones took the ball out the back from Steff Hughes, the space opened up on the right. Johnny McNicholl broke the defensive line and his underarm offload sent Conbeer over in the right corner. The outhalf missed the extras, but Scarlets were good value for their 5-0 lead.
Connacht's misfortune continued when Jack Carty kicked his restart straight into touch, but they gradually grew back into the game with their powerful back row to the fore. A good carry from Paul Boyle threatened Scarlets, while the concession of a penalty at scrum time allowed the home side to get an experience in the Scarlets 22.
And although Scarlets stole the initial lineout throw, Connacht regained possession, and following a brilliant carry from Ultan Dillane, No.8 Abraham Papali'i twisted over the try-line and Carty converted from under the posts.
If Papali'i was posing problems for Scarlets defence with his powerful ball carrying, Sione Kalamafoni was doing likewise for the Llanelli side, and Carty did well to halt his progress on the half-hour mark when he launched off the back of a Scarlets scrum.
But there was no stopping Scarlets eight minutes from the interval when Conbeer ran in his second try. Again the move was launched off a maul on the left touchline, and with a penalty advantage to work with, McNicholl was again put away, and following his dummy pass, he sent the winger over for his second of the half – a carbon copy of the first. Jones was off target with the conversion, but Scarlets led 10-7.
Kalamafoni continued to amass yards with ball in hand and he almost freed Steff Evans five minutes from the break, only for a knock-on to stall their progress. But from the scrum that followed, Conor Kenny was penalised and Dan Jones slotted the penalty kick from the left for a 13-7 interval lead.
Connacht needed a big start to the half and Boyle almost gave them that, but his kick trickled into touch. Moments later McNicholl set Scarlets on the way to their third try when he returned a loose kick and Blacker finished off. With a 20-7 lead to protect, Scarlets sought to keep it tight, but they needed a brilliant cover tackle from Blacker to keep John Porch out. Connacht looked certain to score after 47 minutes but Matt Healy knocked on a yard from the line.
Dillane barged over for a Connacht try midway through the half, but in shocking conditions they couldn't force a winner.
