Fly-half Sam Davies struck a last-gasp drop-goal to snatch victory for Dragons over Scarlets in an absorbing first festive Welsh derby of the Pro14 season.

Scarlets led 17-16 after an eventful first half in which the teams shared three tries - Gareth Davies and Ken Owens for the visitors, Rhodri Williams the hosts - and two yellow cards.

The second half was a grittier affair, heavy rain at Rodney Parade forcing both sides into handling errors.

And after Davies traded penalties with Leigh Halfpenny, the Dragons fly-half struck the match-winning goal with the last kick of the game to spark delirious celebrations.

Davies' team-mates mobbed him after his decisive kick, piling on each other in the mud to revel in a rare win over Scarlets.

The Llanelli-based side had won nine of their previous 10 matches against Dragons but, significantly, the Gwent region's only victory in that sequence had come in the teams' most recent meeting, a thrilling 34-32 Judgement Day triumph last season.

That nine-try encounter set a high standard of entertainment for this fixture and, while driving rain at Rodney Parade made such a scoreline unlikely, this match was packed with incident and played at a breathless tempo.

Scarlets came close to taking the lead after just 12 seconds as scrum-half Davies kicked a loose ball beyond the Dragons' try-line and, although Halfpenny leapt on it, the full-back was judged by television match official Ian Davies to have lost control of the ball over the line.

Dragons ill-discipline

Halfpenny soon kicked a penalty to put the Scarlets 3-0 in front, but the visitors' poor discipline undid their early good work, with Aaron Shingler and Jake Ball among the offenders as Davies kicked Dragons into a 9-3 lead.

It was the home side, however, whose ill-discipline proved costliest as lock Matthew Screech was shown a yellow card for entering a maul from the side.

During his time in the sin-bin, Scarlets scored two converted tries, first as scrum-half Davies sniped over from close range and then as his Wales team-mate, hooker Owens, dabbed down after a mighty rolling maul from the visitors.

At 17-9 up, Scarlets were threatening to pull clear, but Dragons fought back with a fine score of their own as captain and scrum-half Williams threw an outrageous dummy before darting over for a try against his former side.

Davies converted and, in the aftermath of the try, Scarlets prop Wyn Jones was sin-binned for his involvement in a scuffle.

Dragons were unable to take advantage of their numerical advantage in the second half as the continuing downpour and handling errors prompted both sides to favour a conservative kicking strategy.

With no points scored in the first half an hour after the interval, the final 10 minutes of the match looked like being a battle of who could make the fewest mistakes.

Tension and high drama

It proved to be a finale of extreme tension and high drama.

With four minutes left, Davies kicked his fourth penalty to regain the Dragons' lead, but that lasted only 90 seconds as Halfpenny responded with a three-pointer of his own to put the visitors 20-19 ahead.

The nervous mistakes kept coming, Scarlets replacement fly-half Ryan Lamb inexplicably tripping Ross Moriarty and presenting Davies with a reasonably straightforward penalty - but the former Ospreys player missed what looked like the last chance to snatch victory.

However, there was still one final twist to come.

As the clock turned red for the final phase of the game, Dragons had penalty advantage, but they did not need it as Davies struck a sweet drop-goal from the edge of the Scarlets 22 to secure a memorable victory.

Dragons director of rugby Dean Ryan said:

"I'm just really pleased for the lads because it was one of those games where there wasn't a huge amount of rugby played and you just had to stay in it.

"We keep talking all week about playing rugby and then we get to Friday and think 'It's probably not going to be this week'. We can play a bit as well and I think the learning experience for this group is the combination of both.

"On nights like tonight, that [the weather] dictates what the game is. You deserve some good times if you put a shift in so the boys deserve a good time."

Scarlets head coach Brad Mooar said:

"We certainly took control of it for the middle period of the first half and thought we had the recipe for taking the game away from the Dragons.

"But they hung in there and we certainly gave them plenty of opportunities with errors, poor discipline and they took those chances, so well done to the Dragons.

"You're not going to get any favours away so you've got to make sure you play to the interpretation of the officials and also the conditions.

"All of that is in our control and I think we handed the opportunities to the Dragons."

Dragons: Will Talbot-Davies; Owen Jenkins, Adam Warren, Jack Dixon, Ashton Hewitt; Sam Davies, Rhodri Williams (capt); Brok Harris, Elliot Dee, Leon Brown, Joe Davies, Matthew Screech, Cory Hill, Taine Basham, Aaron Wainwright.

Replacements: Richard Hibbard, Aaron Jarvis, Lloyd Fairbrother, Brandon Nansen, Ross Moriarty, Tavis Knoyle, Jacob Botica, Tyler Morgan.

Scarlets: Leigh Halfpenny; Johnny McNicholl, Steff Hughes, Hadleigh Parkes, Steff Evans; Dan Jones, Gareth Davies; Wyn Jones, Ken Owens (capt), Samson Lee, Jake Ball, Sam Lousi, Aaron Shingler, Josh Macleod, Uzair Cassiem.

Replacements: Ryan Elias, Phil Price, Javan Sebastian, Tevita Ratuva, Blade Thomson, Kieran Hardy, Ryan Lamb, Corey Baldwin.

Referee: Ben Whitehouse (Wales)

Assistants: Mike English (Wales) & Gareth John (Wales)

TMO: Ian Davies (Wales)