International fly-half Kris Burton put the men of Gwent into the lead early on by kicking a penalty over the posts. But it was a short-lived lead as, after Priestland made ground, lock Ball was on hand to drive on before scoring with an outstretched arm.
Priestland added a conversion and a penalty then went onto kicking all three conversions for the Scarlets, three tries that followed.
However Newport Gwent Dragons struck back after Burton intercepted a pass from the Scarlets and headed for the try line. As the Scarlets caught up with him, he passed the ball to Pat Leach who then in turn passed it to Tom Prydie who crossed the white wash. Burton converted and the whistle was blown for half time.
Half Time: Scarlets 24 Dragons 13
The visitors came out and reduced the deficit with another Burton penalty. But Scarlets hooker Ken Owens replied with a try and it was again converted by Priestland. But Dragons number eight Taulupe Faletau stole possession at a ruck and Prydie made the most of a cross-kick to out-pace the remaining defence and Tovey converted.
But the hosts were on the attack once again as the Dragons gave away a penalty, so Priestland added two more points to the board before the final whistle was blown. The final scores for teh game were Scarlets 34 Dragons 23.
Steven Shingler, Kristian Phillips, Jonathan Davies (c), Olly Barkley, Jordan Williams; Rhys Priestland, Gareth Davies; Phil John, Ken Owens, Samson Lee, Jake Ball, George Earle, Josh Turnbull, John Barclay, Rob McCusker, John Barclay.
Replacements: Frazier Climo, Gareth Maule, Rob Evans, Kirby Myhill, Rhodri Jones, Johan Snyman, Aaron Shingle, Rhodri Williams.
Hallam Amos, Tom Prydie, Pat Leach, Jack Dixon, Will Harries, Kris Burton, Richie Rees; Phil Price, T. Rhys Thomas, Bruce Douglas, Andrew Coombs (c), Matthew Screech, Lewis Evans, Taulupe Faletau, Nic Cudd.
Replacements: Tyler Morgan, Jason Tovey, Jonathan Evans, Owen Evans, Duncan Bell, Sam Parry, Jevon Groves, Darren Waters.
Man of the Match: Josh Turnbull