Two tries just before the interval were key for Scarlets, as they ran out convincing 40-17 winners over the Ospreys to seal third place in the Guinness PRO12 standings.

A home semi-final was always going to be out of the region’s reach heading into the final round, but that did not stop Scarlets putting in an imperious performance against their Welsh rivals.

They led 23-10 at the break despite Keelan Giles grabbing the first try of the day, as the boot of Rhys Patchell kept them in touch before Will Boyde and Steff Evans crossed the whitewash while Rhys Webb was in the sin bin.

And two more tries after the interval from Aaron Shingler, Johnny McNicholl, and the superb Jonathan Davies put the hosts out of sight – and regardless of Dan Baker’s consolation score, Scarlets will travel to Leinster for their Guinness PRO12 semi-final full of heart.

It was the Ospreys who flew out of the blocks, winning a penalty which was dispatched by Dan Biggar with just a minute played.

And while Scarlets thought they had immediately hit back with a try, the TMO ruled out Ken Owens’ effort on five minutes, with the hooker adjudged to have just been tackled into touch before dotting down.

Rhys Patchell struck a penalty of his own through the posts however just a minute later to level the scores, with Biggar the man penalised.

The fly-half soon made amends as Ospreys scored from Biggar’s offload; Giles still had a lot of work to do to wriggle out of Owens’ tackle, and somehow the youngster stretched over the line to complete a brilliant finish.

Biggar made no mistake with the routine conversion from the left, and it was 10-3 to the visitors on 12 minutes.

Successive Patchell penalties on 17 and 23 minutes pegged the Ospreys back however, and the warning signs were there for the visitors as Davies made a bulldozing break up the field.

And there was a huge moment in the game on 28 minutes as Rhys Webb saw yellow for a high tackle on Owens with the Scarlets bearing down on the line.

The hosts looked to make their numerical advantage count immediately, and as they put the ball through the hands it looked like McNicholl had scored in the left corner – but again they were denied by the TMO who spotted a knock-on at the breakdown in the build-up.

But while Webb was still off the field, Boyde went over on the right as the Scarlets once again put the ball through the hands and made use of the space.

And a sublime break from No.9 Gareth Davies – off the back of a scrum inside his own half – paved the way for a sucker-punch try just before half time for the Scarlets, as he offloaded to Jonathan Davies who in turn found Evans to finish off the brilliant breakaway under the posts.

And while the Ospreys kept their hosts at bay for the first 20 minutes of the second period, when Shingler went over on the hour mark the floodgates opened.

It was Liam Williams who made the initial break and offload, with the effervescent Jonathan Davies there to collect his pass, and Scarlets were lining up in support with Shingler eventually the benefactor to score under the posts.

Two more tries in the final ten minutes put the gloss on the win; first Evans’ sublime offload out the back of his hand released the rapid McNicholl around the outside, before the winger was again provider as he collected Jonathan Davies’ kick and offloaded for the onrushing centre to complete the rout

There was still time for Baker to burrow over with a minute remaining, but the nature of this derby victory will have left Wayne Pivac purring ahead of the Guinness PRO12 semi-finals.

The Guinness PRO12 Final takes place on May 27 at Aviva Stadium, Dublin. Fans can guarantee their place by booking their tickets via www.ticketmaster.ie