Barry Williams marked his return to action with a brace of tries as Neath comfortably saw off their new regional partners Swansea.

The sides are joining forces next season, but in their final meeting as professional clubs there was only one team in it.

Resuming after 10 weeks out through injury, former British Lion Williams helped Neath to eight tries, every one of which was converted.

There were also second-half scores from Patrick Horgan, Adrian Durston and replacement Matthew Jones.

For Swansea, Arwel Thomas crossed for two tries and there was one apiece for Richard Rees and Gareth Swales.

Neath led 28-3 at the break after running in four tries during a one-sided first half.

Wing Kevin James started the ball rolling when he powered across in the corner after being freed by Durston.

As Swansea tried to counter, James Storey cut through non-existent tackling some 75 metres out before putting fly-half Shaun Connor over from halfway.

Thomas checked the black tide with a penalty, but Neath were soon back in the groove with man-of-the-match Williams profiting from a charge-down to crash over. Dave Tiueti hammered another nail in with a fine score after good work by Connor.

Swansea hit back after the break by matching Neath try for try, with Thomas swooping for a quick-fire double and Rees and Swales finishing impressively, but the outcome was never in doubt.

Neath coach Lyn Jones was in buoyant mood after his side extended their lead at the top of the Welsh Premiership to four points.

"We scored some nice tries and there was quite a bit to be encouraged by," said Jones, who will coach the new Neath-Swansea regional side next season.

"It was a typical end-of-season encounter with lots of movement and a willingness to have a go.

"I am pleased with the result because I want Neath to win the league, but it was also good to see so many youngsters coming through for Swansea."

Swansea trailed 28-3 at half-time but matched Neath 4-4 on tries after the break to underline their spirit.

"We never gave up and that was good to see," said Swansea coach Paul Moriarty.