Pro12: Scarlets 40-17 Ospreys
|Scarlets (23) 40|
|Tries: Boyde, Evans, Shingler, Mcnicholl, Davies Cons: Patchell 3 Pen: Patchell 3|
|Ospreys (10) 17|
|Tries: Giles, Baker Cons: Biggar, D Evans Pens: Biggar|
Dominant Scarlets claimed third place in the Pro12 with a record win over Ospreys, who finished fourth, in Llanelli.
First-half tries by Will Boyde and Steff Evans while Ospreys skipper Rhys Webb was in the sin-bin put them in control at half-time.
Scarlets added tries by Aaron Shingler, Johnny Mcnicholl and Jonathan Davies.
Scarlets will play Leinster away in the play-offs while Ospreys must regroup before facing Munster in Limerick.
Leinster host Scarlets on Friday, 19 May while Ospreys' game at Thomond Park takes place a day later.
Keelan Giles's early try put Ospreys ahead early on, while Dan Baker's score late on was nothing more than a consolation.
Fitting send-off for Williams and Der Merwe
The winning margin of 23 points eclipsed Scarlets' previous biggest win over their local rivals, 30-17 in 2006.
It was a fitting send-off in front of a jubilant crowd of 13,326 for departing Scarlets Liam Williams and DTH van der Merwe.
It also underlined the Ospreys' dramatic loss of form following the Six Nations, which saw them lose four out of five matches in the Pro12.
Scarlets were completely dominant, taking advantage of a shaky Ospreys set-piece and indiscipline.
Another concern for the Swansea region was an ankle injury which saw Dan Biggar limping off early in the second half.
Ulster's failure to pick up a high-scoring win over Leinster in Belfast means there are two Welsh teams in the Pro12 play-offs for the first time since the system was introduced
Scarlets went off like a train following Biggar's first-minute penalty and were denied an early try after the TMO ruled Ken Owens had a knee in touch before touching down - Rob Evans' outstanding slip pass deserved better.
Patchell brought the home team level before Giles showed great strength to touch-down for Ospreys.
Scarlets had the upper hand and made Ospreys pay for indiscipline and handling errors following captain Rhys Webb's yellow card for a high tackle on Owens.
A Johnny Mcnicholl touchdown was eventually ruled out for a knock-on spotted by the TMO.
But it was a temporary reprieve as Will Boyde eventually touched down wide on the right after Ospreys had failed to clear the line and were then penalised at a defensive line-out.
Within a minute another error - a knock on deep in Scarlets' territory - led to scrum-half Gareth Davies breaking brilliantly from the resultant scrum with Evans touching down.
All the time Webb was a frustrated spectator in the sin-bin as his team conceded 14 points.
Ospreys never recovered, and spent most of the second half defending valiantly before finally breaking in the face of waves of attacks.
Shingler, Mcnicholl and Davies' tries were all the result top-drawer back play and several other chances went begging.
The scoreline does not lie. This game was as one-sided as 40-17 suggests.
Scarlets coach Wayne Pivac told BBC Radio Wales: "I'm very pleased. We've been building nicely and I was pleased with the way the boys continued to push to score tries and I thought we left a few out there in the first half.
"A record win means a lot for the region. I understand what it means to the locals and it certainly was one we'll hold dearly for a while because it was a very good performance."
Ospreys coach Steve Tandy told BBC Radio Wales: "We had a lot of injuries and didn't implement some of the things we wanted to do, but in fairness to the Scarlets every time we turned over the ball they looked like they were going to score.
"Over a 22-week season we've got to the semi-finals, we've definitely stuttered of late, but ultimately the Scarlets thoroughly deserved their win."
Scarlets: Johnny Mcnicholl; Liam Williams, Jonathan Davies, Scott Williams, Steff Evans; Rhys Patchell, Gareth Davies; Rob Evans, Ken Owens (capt), Samson Lee, Lewis Rawlins, Tadhg Beirne, Aaron Shingler, Josh Macleod, Will Boyde.
Replacements: Ryan Elias, Wyn Jones, Werner Kruger, David Bulbring, Tom Price, Jonathan Evans, Hadleigh Parkes, DTH van der Merwe.
Ospreys: Dan Evans; Keelan Giles, Kieron Fonotia, Josh Matavesi, Tom Habberfield; Dan Biggar, Rhys Webb (capt); Nicky Smith, Scott Baldwin, Rhodri Jones, Bradley Davies, Tyler Ardron, Sam Underhill, Justin Tipuric, James King.
Replacements: Scott Otten, Paul James, Dan Suter, Lloyd Ashley, Dan Baker, Brendon Leonard, Jonathan Spratt, Dafydd Howells.
Referee: Nigel Owens (WRU)
Assistant referees: Dan Jones (WRU), Wayne Davies (WRU).
TMO: Jon Mason (WRU)