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Ospreys dominate first half at Swansea.com Stadium, scoring four tries to Scarlets' one to lead 26-7 at the break.
Scarlets improve in second half but fail to take their chances, as Ospreys cruise to a 36-14 win to reach the quarter-finals
Ospreys will face Lyon in the last eight at the Swansea.com Stadium at 17:30 BST on Saturday, 12 April
Ospreys 19-7 Scarlets
Richie Rees
Former Wales international on BBC Radio Wales
Reuben Morgan-Williams has absolutely been the best player of the opening half-hour.
Between him and Dan Edwards they've been absolutely running the game.
Rhys Davies try, Dan Edwards con
Image source, Huw Evans Picture AgencyOspreys get a third.
It actually came from a dropped pass in midfield that Scarlets got their finger tips to.
But Dan Kasende ends with his hands on the ball, he's tracked by Macs Page but the big Ospreys second-row is in support and even three defenders can't stop him getting the ball down.
Ospreys 12-7 Scarlets
Oh take a bow Dan Edwards... a superb 50-22 that was absolutely on-point.
Nothing Blair Murray could do about that one.
Ospreys attacking lineout.
Ospreys 12-7 Scarlets
Richie Rees
Former Wales international on BBC Radio Wales
That was a sign that the Ospreys ran out of ideas, they weren't getting much success running through the middle so felt like they had to try the long-range drop goal.
Ospreys 12-7 Scarlets
Well after all that time inside the 22, Dan Edwards takes a pot-shot from 40 metres and it's wide.
Ospreys 12-7 Scarlets
It's only a brief respite for Scarlets because it's just wave after wave of Ospreys attack.
Scarlets somehow survive.
Gareth Thomas barged his way to the line. It looked for all the world that he had go the ball down but somehow a red jersey got their arm under him and Scarlets get to clear.
Ospreys will be frustrated at coming away empty-handed from that five-minute period inside the 'red zone'.
Big boost for Scarlets.
Ospreys 12-7 Scarlets
Keelan Giles races onto a fizzing pass from Reuben Morgan-Williams but is just edged into touch at the corner flag.
But it's another penalty for Ospreys.
Image source, Getty ImagesOspreys 12-7 Scarlets
Richie Rees
Former Wales international on BBC Radio Wales
Scarlets have been left off the hook there after the forward pass, the Ospreys are really looking comfortable today.
Ospreys 12-7 Scarlets
Ospreys send up some big hitters in Dewi Lake, Jac Morgan and Gareth Thomas and eventually another penalty comes for Josh Macleod's no-arms tackle.
Easy three points on offer but Ospreys go for the scrum.
They fancy this one.
Ospreys 12-7 Scarlets
Ospreys' driving lineout wins a penalty and Justin Tipuric immediately reacts at Vaea Fifita. He didn't like something then by the Scarlet.
Ospreys kick to the corner again.
Ospreys 12-7 Scarlets
Richie Rees
Former Wales international on BBC Radio Wales
You have to feel for Reuben Morgan-Williams, he hasn't been capped yet but he's been so consistent, you have to imagine he's frustrated.
Image source, Huw Evans Picture AgencyOspreys 12-7 Scarlets
How did Reuben Morgan-Williams stay in touch then?
Tip-toing the line and even manged to stay in when he was swung to the ground by Vaea Fafita!
Ospreys 12-7 Scarlets
Ospreys number eight Morgan Morris just took a backhand to the chops then as referee Matthew Carley put his hand out to award a scrum!
Yellow card?
Ospreys 12-7 Scarlets
Oh this is disappointing for Scarlets as hooker Ryan Elias trudges off.
Can't see what the injury is but looks like his day may be over.
Marnus van der Merwe is on.
Ospreys 12-7 Scarlets
Yes Richie, we could not have asked for a more exciting start to this knockout derby!
Ospreys 12-7 Scarlets
Richie Rees
Former Wales international on BBC Radio Wales
Really exciting rugby from the Scarlets, what an opening 11 minutes to this game.
Macs Page is one of the Scarlets' stand-out players, he's really come into his own over the last eight or nine weeks.
Blair Murray try, Ioan Lloyd con
Image source, Huw Evans Picture AgencyOh hang on, Scarlets have woken up.
The Wales full-back skips over to get the visitors on the board but that was all about the handling skills of Joe Roberts and Ioan Lloyd.
They combined to release Macs Page who steps inside two men before sending Murray in for an easy finish.
Game on!
Ospreys 12-0 Scarlets
Justin Tipuric leaps like a salmon to steal that lineout from Sam Lousi's grasp just 10 metres from the Ospreys try line and the hosts boot is clear.
Ospreys 12-0 Scarlets
Yes Gareth, Ospreys will have last week's comeback by Scarlets right at the front of their minds.
Right then... what have the Scarlets got?
They need a response and captain Josh Macleod wins a turnover penalty.
