But Wigan were not going to roll over and they took the lead again when Carmont picked up a loose pass and ran through a large hole in the Dragons defence to score from 60 metres out.
The Scarlets stretched their lead after the break when Williams found a huge hole in the Blues midfield to scamper through and send lock Day over for an unconverted try.
The dangerous-looking Watmough extended the lead when a delightful pass by Orford created a hole in the Leeds defence and the second-rower got through to score.