Pro12: Scarlets 6-10 Ospreys
Scarlets (3) 6
- Priestland 2
Ospreys (0) 10
A late try from Ian Evans saw Ospreys come from behind to win at Scarlets in a fierce Pro12 Welsh derby.
The British and Irish Lions lock had not figured in an Ospreys match squad since October, but came off the bench to play a crucial part.
With Scarlets leading 6-3 late in the game Evans gathered an attacking line-out and was shunted over for a try.
Dan Biggar added the conversion to an earlier penalty, with Rhys Priestland having kicked all Scarlets' points.
The full-bloodied commitment demanded of derbies between the Welsh regions was clearly evident in some fierce early exchanges.
Each impact was roared on by a pleasingly full Parc y Scarlets crowd, which had settled in to enjoy the Boxing Day rugby after a pre-match demonstration by some of the regional fans protesting against the Welsh Rugby Union in the political power struggle affecting the sport.
But the quality suffered in the frenetic action and both sides were guilty of wasting good opportunities to claim an opening try.
After Richard Hibbard's loose, blind pass had put Ospreys under pressure, Scarlets allowed their visitors to wriggle away from their own line, although Sam Lewis should take credit for some good tidying work.
Then Ospreys scrum-half Rhys Webb broke down the middle from a ruck to find Biggar in support, but the rest of his backs were not so alert and left their team-mates isolated with no support.
Instead it was left to Priestland to give Scarlets the lead with a penalty, while Frazier Climo was unfortunate not to double the hosts' lead when his long-range kick came back off a post.
Ospreys had seen plenty of the ball but all too often were wasteful or lacked patience - with full-back Sam Davies particularly guilty of kicking away possession with other options available
A long-range drop-goal attempt from Biggar and an even longer penalty chance, from just inside his own half, was the closest the visitors came to points in the first half.
If the scoreboard was providing scant cheer for either set of fans, the physical battle was at times mesmerising.
Scarlets blind-side Aaron Shingler had been particularly outstanding in the first period, even among some fine performances from his comrades in red, while Hibbard, Ryan Jones and Alun Wyn Jones were first among equals in a busy Ospreys pack.
Biggar's first-half penalty miss had been his first failure in 36 attempts and the Ospreys fly-half was also just wide with a second, easier kick soon after the restart.
Instead it was Priestland, Biggar's rival for the Wales number 10 shirt, who doubled Scarlets' lead after Alun Wyn Jones had been penalised for taking a lifter out at a line-out.
Hanno Dirksen was unfortunate not to give Ospreys a try after being released down the right by Davies, but a long look by the TMO ruled that Kristian Phillips and Scott Williams had done just enough to bundle the wing into touch before he grounded the ball.
With 12 minutes remaining Ospreys finally got themselves on the scoreboard as Scarlets failed to roll away from a tackle, allowing Biggar to make it 6-3 and set up a nervous, thrilling finale.
Another penalty coughed up at a ruck was just out of Biggar's range, so instead the stand-off sent a pin-point kick spiralling deep into Scarlets territory to set up a five-metre line-out.
Evans, who had earlier replaced James King at lock, gathered cleanly and was driven over the line for a try converted by Biggar.
Ospreys still had to weather a series of Scarlets five-metre line-outs, losing Alun Wyn Jones to the sin-bin in the process, but held out for a dramatic and hard-won victory and move to second in the Pro12 table.
Scarlets: Liam Williams; Kristian Phillips, Nick Reynolds, Scott Williams, Frazier Climo; Rhys Priestland, Gareth Davies; Phil John, Ken Owens, Samson Lee, Jake Ball, George Earle, Aaron Shingler, Rob McCusker (capt), John Barclay.
Replacements: Gareth Maule for L. Williams (57), Aled Thomas for Reynolds (72), Rob Evans for John (66), Emyr Phillips for Owens (39), Rhodri Jones for Lee (66), John Snyman for Ball (70), Richard Kelly for S. Shingler (78). Not Used: Rhodri Williams.
Ospreys: Sam Davies; Hanno Dirksen, Ashley Beck, Ben John, Jeff Hassler; Dan Biggar, Rhys Webb; Duncan Jones, Richard Hibbard, Adam Jones, Alun Wyn Jones (capt), James King, Joe Bearman, Ryan Jones, Sam Lewis.
Replacements: Tom Isaacs for John (53), Tito Tebaldi for Webb (70), Aaron Jarvis for Adam Jones (49), Ian Evans for King (66), Tyler Ardron for Bearman (63), Morgan Allen for R. Jones (66), Scott Baldwin for Hibbard (55). Not Used: Marc Thomas.
Sin Bin: A W Jones (79).
Referee: Leighton Hodges (WRU)
Assistant Referees: Sean Bricknell, Wayne Davies (both WRU)
Citing Commissioner: Russell Howell (WRU)
TMO: Tim Hayes (WRU)