Scarlets made the Guinness PRO12 final for the first time after a brave defensive display in the second half was enough to see off Leinster.

The Welsh side became the first away team to win a PRO12 semi-final and they had to do it for the majority of the game with 14 men after Steff Evans was sent off at the end of the first half.

Scarlets ran in three tries in the first half to take a commanding lead but were forced to defend in the second period, although Leinster failed to take advantage of the extra man.

Liam Williams scored two late penalties to take the game away from Leinster and book their place at the Aviva Stadium next week where they will play the winner of the second semi-final between Munster and Ospreys

Scarlets took the lead after just nine minutes when Evans finished off a good move started by Jonathan Davies who wriggled through a tackle on a counter-attack, got it out to John Barclay who released the winger to finish it off with an electric burst of pace, Rhys Patchell adding the conversion.

The hosts got themselves on the board when Isa Nacewa slotted a penalty after Scarlets second row Lewis Rawlins was penalised for not releasing his man in the tackle.

Leinster looked to add to that score straight away as they went on the attack with Joey Carbery working his way through the Scarlets defence but the Welshmen managed to regain possession.

Leinster continued to pile on the pressure and scrum-half Luke McGrath was only denied a try after excellent defensive work from Evans who made a late tackle and Williams got over the ball to snatch it back for the visitors.

But the pressure finally told as the Irish outfit went over for their first try.

A well-worked team move was finished off by Garry Ringrose. The Leinster centre ran at pace and took an offload from Jack Conan before crossing the line and Johnny Sexton added the extras to make it 10-7.

But no sooner had Leinster scored their try than Scarlets replied with one of their own.

This time it was Aaron Shingler who burst through a huge gap and combined with scrum-half Gareth Davies to go over the line straight from the restart, before Patchell duly added the conversion.

And minutes later they ran in another try, this time after an offloading masterclass from Scott Williams, James Davis and Evans sent Davies in under the posts for one of the best tries of the season. And again Patchell added the extras to put Scarlets 21-10 ahead.

But with half-time approaching Scarlets were reduced to 14 men as Evans was sent off for a tip-tackle on Ringrose.

Leinster went for the corner with the resulting penalty but the Scarlets were able to clear andhold on for the interval.

The visitors were forced to put in a real defensive shift in the second half as they looked to protect their 11-point advantage.

There was a huge cheer around the RDS Arena as Leinster’s Hayden Triggs left the field for the final time before he retires at the end of the season and he was replaced by Devin Toner.

The pressure of the extra man finally told when Leinster stole the ball at the line-out and then used their power to push for the line. Eventually Conan dotted down but Nacewa missed the chance to reduce the lead even further as he failed with the conversion.

And Scarlets were able to extend their lead on a rare venture into the Leinster half when Liam Williams slotted a penalty to extend their lead.

And they won another penalty with just two minutes remaining, which Williams converted, to complete the job and make it back to Dublin for next week’s final.

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

Further information: www.pro12rugby.com/final