Scarlets took a step towards the European Champions Cup quarter-finals and dented Bath’s hopes with a bonus-point victory at the Recreation Ground.
It was a scintillating display of attacking rugby by the visitors, who scored four tries before Matt Banahan and Zach Mercer replied for Bath.
The Welsh side replace Bath at the top of Pool Five and lead on 17 points with one round of games remaining.
Bath are second on 13 points, alongside Toulon, who play Benetton on Sunday.
Scarlets now have their destiny in their own hands and host three-time winners Toulon in their final game on 20 January.