Ceri Sweeney narrowed the margin with two penalty goals, before Dragons backrower Ian Gough was yellow-carded for a high tackle on Scarlets centre Salesi Finau and Finau himself was binned for a high shot of his own. Watkins bagged his second try after a Gareth Bowen chip through, and Bowen slotted a last-second dropped goal as his side ignored the wind to take a 22-16 lead at halftime.
Bowen and Sweeney traded penalty goals before Scarlets backrower Simon Easterby was yellow-carded for persistent infringing, and Dragons No 8 Michael Owen took advantage to power his way over from a close-range scrum. Sweeney's conversion gave his side a one-point lead with 10 minutes left on the clock. Dragons centre Sione Tuipulotu was the next man to earn a yellow card and Bowen's penalty goal in the 79th minute gave his side the lead. His next act was to convert Dafydd Jones' second try and deny the Dragons a losing bonus point.
Scarlets: Tries - M Watkins 2, D Jones 2; Pens - G Bowen 2; DG - G Bowen; Cons - G Bowen 3
Dragons: Tries - K Morgan, M Owen; Pens - C Sweeney 4; Cons - C Sweeney 2
Halftime: Scarlets 22-16
Yellow card: I Gough (Dragons), S Finau (Scarlets), S Easterby (Scarlets), S Tuipulotu (Dragons)