British & Irish Lions hopefuls Jonathan Davies and Liam Williams struck in the final quarter of the game to help the Scarlets to a 21-16 win over the Dragons at the Principality Stadium on Saturday.

The victory also strengthened the Scarlets' position in the race for the Guinness PRO12 play-offs. The west Walians safely avoided an upset on PRO12 Welsh Judgement Day thanks to tries by Lions hopefuls Jonathan Davies and Liam Williams after they had trailed 6-3 at the break.

It may not have been pretty but it was job done for Wayne Pivac's side, who have won 15 of their last 17 in the PRO12, after their neighbours the Ospreys were beaten by Cardiff Blues in the first game of the Welsh double-header in Cardiff.

With Ulster also suffering defeat away to second-placed Munster, it was a good day for the third-placed Scarlets while the Dragons continue to struggle at the other end despite a spirited showing that got the bonus point they deserved with a last-gasp Adam Hughes try.

It was the Dragons that started well to take a 6-0 lead after a quarter of an hour thanks to a pair of penalties from fly-half Angus O'Brien.

The Gwent side had not won in any competition since January and were looking nervously over their shoulder at the Italian pair of Treviso and Zebre.

However, they played with plenty of spirit to turn the game into something of an arm-wrestle, giving little opportunity for the Scarlets' dangermen Scott Williams, Jonathan Davies and Liam Williams to threaten.

The west Walians got on the scoreboard with a penalty from outside half Dan Jones after 26 minutes but that was the end of the scoring for the first half with both sides wasting driving lineout opportunities close to the line.

The Scarlets needed to up the tempo in the second half and they duly went on the attack in the 22 only for back row forward John Barclay to be held up in a tackle just shy of the line.

That chance went begging but the west Walians were enjoying more of the ball and in good areas with that pressure allowing Jones to level up in the 50th minute. The Scarlets were in front on the hour when they exploited a man advantage after Dragons wing Hughes was sin-binned for killing the ball in the 22.

Seconds later the ball was worked through the hands for Wales centre Davies to canter over for a score that Liam Williams improved for a 13-6 lead. To their credit, the Dragons responded with a third O'Brien penalty only for Williams to swiftly cancel that out to make it 16-9 in the 68th minute.

And the Wales full-back/wing applied the killer blow himself when he showed pace to over on an arcing run inside the 22 with nine minutes left before the Dragons earned a bonus point at the death with a score by Hughes converted by O'Brien.