Nigel Davies’ men made it three wins from three group games as they saw off their English rivals 27-19 at Parc y Scarlets.
A brace of tries from Tongan wing Vili Iongi and a third score from replacement prop Deacon Manu saw the Scarlets move four points clear at the top of Pool 3 with just one round of matches left to play.
Gloucester’s bonus-point win over the Blues had heaped the pressure on the Scarlets ahead of kick off but their latest LV victory now leaves them on the edge of a place in the last four.
The Scarlets now know a draw at Sale next Saturday night would be enough to take them through to the knockout stages even if Gloucester pick up maximum points against Irish at the Madejski Stadium earlier in the day.
Iongi’s opening score three minutes before the half-hour mark handed the Scarlets a 10-3 lead at the break as he rounded off a fine move involving Aled Thomas and Dan Newton.
A quick-fire brace of penalties from the prolific boot of Tom Homer narrowed the gap to 10-9 inside the first 10 minutes of the second period but Manu’s close-range score after an error from Exiles wing Topsy Ojo gave the Scarlets some breathing space once more.
Manu barged over after solid work from the entire pack and, when Newton converted, the Scarlets were eight points to the good on 57 minutes.
But the two-score lead didn’t last long, though, as Homer added a third penalty before Ojo made amends for his earlier spill with a 61st minute converted score that had Irish in front.
The Scarlets could easily have folded but they refused to let their heads drop and it was they kept their composure late on. Newton kicked them back in front with a penalty 13 minutes from time and Iongi added the final blow with a late, late effort that came just moments after Irish had been looking for a winning try of their own.
