Outside half Rhys Priestland bagged a fifth, as well as 12 points with the boot, whilst flanker Josh Turnbull and the outstanding Ashley Banfield raced over to complete the rout. The Dragons stayed in contention for a short while in the first half, but despite a try from Richard Wilkes and a penalty and conversion from Ashley Smith, they were outgunned in a second half which saw the Scarlets run up 19 points without reply.
Team manager John Davies was delighted with his side's return on the night. "To win with a bonus point and to play in the manner that we did, was very pleasing. We just have to maintain our standards in the three remaining rounds."
Meanwhile the Ospreys did their chances no harm with a comfortable victory over the Blues at St Helens. There were five tries in all for the Ospreys with James Pike helping himself to a couple in his side's 35-8 success.
The Blues have struggled this season to gather any momentum despite being tipped at the beginning of the season as one of the probable front-runners. Gareth Williams-Davies kicked a penalty for them in the first half and Jamie Roberts added a second half try.
However, the Ospreys, after being held early on, were head and shoulders above their visitors with Pike, Lee Bevan and Sam Kiley crossing for first half tries. Jason Howells and Pike with a second scored in the second half with Jonathan Spratt adding a couple of conversions and as many penalties.
Ospreys' coach Gethin Watts said, "It was tight early on but once we went over for our first try we took control. In the second half we played really well and in the end deserved to win it as we did."
Next Wednesday it's the turn of the U18 with the Ospreys and Blues meeting at Aberavon and the Dragons travelling to play the Scarlets.