Llanelli Scarlets advanced to the Celtic Cup final by knocking out League champions Neath-Swansea Ospreys in a breathless encounter at Stradey Park.
CELTIC CUP SEMI-FINAL
Scarlets: (7) 23:
Tries: J Davies, G Quinnell.
Cons: C Thomas 2.
Pen: C Thomas 2, B Davies.
Ospreys: (12) 15:
Pens: M Jones 5.
Replacement back-row Gavin Quinnell shoved his way over in injury time to give the Scarlets the lead for the first time in the match.
Ceiron Thomas' conversion, plus a long range penalty from Barry Davies to make sure sealed a stunning comeback result.
Ospreys were limited to five penalty kicks from fly-half Matthew Jones.
Young fly-half Jones, called into the Wales squad this week for the tour to North America, kicked four out of six of his first-half penalties as the Ospreys bossed things.
But just when it looked like the Scarlets would finish the first period empty-handed, Lions tourist Dwayne Peel sparked the home side into life.
The Wales scrum-half took a quick tap penalty and scorched through the napping Ospreys defence, allowing veteran prop John Davies to crash over under the posts.
Ceiron Thomas struck the conversion to leave the Scarlets trailing just 7-12 at the break.
Try opportunities were limited by some tough defence and borderline slowing of the ball at the breakdown by both sides.
Scarlets fly-half Ceiron Thomas is tackled by Steve Tandy
So it was left to the two fly-halves to keep the scoreboard ticking over, Thomas bracketing another success for Jones with two of his own to bring the Scarlets to within two points.
It seemed as though the tide was turning the home side's way when the Ospreys had Wales lock Brent Cockbain sin-binned on 63 minutes for preventing quick ball.
The Ospreys weathered the storm for the 10 minutes they were down to 14 men and looked like they would just hang on for the win.
But the Scarlets laid siege to their visitors' line as the clock ground down into time added on, Quinnell - the latest in the famous rugby family dynasty - eventually finding the chink in the armour.
Barrelling over under the posts just like big brother Scott used to do, Quinnell gave Thomas a simple conversion to make it 20-15 to the Scarlets.
There was still plenty of injury time remaining for one last Ospreys effort, but Davies put the Scarlets two scores clear with a mammoth kick from inside his own half to seal a famous win.
It wrapped up a proud day for the region, after the semi-pro Llanelli team had earlier produced a similar last-gasp victory to beat Pontypridd in the Konica Minolta Cup final.
Scarlets: B Davies; G Evans, M Watkins, T Selley, A Havili; C Thomas, D Peel; P John, M Rees, J Davies, A Jones, C Wyatt, S Easterby (capt), G Thomas, A Powell.
Replacements: R Davies, A Gravelle, V Cooper, G Quinnell, M Phillips, G Bowen, S Thomas.
Ospreys: S Terblanche; R Mustoe, D Bishop, E Seveali'i, S Williams; M Jones, J Spice; D Jones, B Williams (capt), A Jones, B Cockbain, J Thomas, J Bater, S Tandy, R Jones.
Replacements: R Hibbard, A Millward, A Newman, R Pugh, S Connor, A Bishop, A Brew.
Referee: Donal Courtney (IRFU).