Wing Henry Speight dives over for Ulster's second try at Parc y Scarlets

Heineken Champions Cup Pool Four: Scarlets v Ulster Scarlets (10) 24 Tries: S Evans 2, D Davies Cons: Patchell 2, D Jones Pen: Patchell Ulster (13) 25 Tries: Stockdale, Speight, Addison, Coetzee Con: Cooney Pen: Cooney

Ulster edged Scarlets in a Champions Cup thriller, to leave the winless hosts' European hopes in tatters at the halfway point of the pool stage.

Tries from Jacob Stockdale, Henry Speight, Will Addison and Marcell Coetzee ensured a bonus-point win that revitalises Ulster's prospects.

Wales wing Steff Evans scored twice to keep Scarlets in touch, while Dan Davies' late try set up a tense finale.

But the home defence was found wanting too often at a gusty Parc y Scarlets.

Scarlets had won here when the two sides met in the Pro14 at the end of November, stretching a six-year losing streak for the Irish side in Llanelli.

Both teams that night were shorn of a host of international players and the stars were back for Europe, although Scarlets were without Wales duo Leigh Halfpenny and Jake Ball as the pair recover from head injuries.

Ulster, meanwhile, had casualties in the shape of Andrew Warwick and Alan O'Connor.

Scarlets had lost their opening two games of the European campaign, the same record they had going into round three last season, after which they won five games in a row to reach the semi-final.

Ulster had at least won their opening game at home to Leicester, before losing at Racing 92, and a famous result in Llanelli means they now have their fate firmly in their own hands.

Wild and windy

Wing Steff Evans claimed two tries for Scarlets

After Scarlets fly-half Rhys Patchell and Ulster scrum-half John Cooney exchanged penalties, the visitors took an early advantage.

Addison made the initial break in midfield, stepping inside Jonathan Davies before releasing wing Stockdale, who raced past Evans and Gareth Davies far too easily to score in the left corner.

Kicking into a tricky wind, Cooney missed the conversion and a later penalty.

Helped by that breeze, Scarlets were able to kick deep into Ulster territory and a sustained period of pressure saw Evans pop up in midfield to squirm over, with Patchell converting.

But five minutes before half-time Speight dived over on the right to give the visitors a 13-10 lead.

The start of the second half was a scrappy affair, with both sides making a string of errors, but Addison added some much-needed quality when he cut back on the angle to score under the posts, Cooney converting.

With their European hopes hanging by a thread, Scarlets responded with a second try from Evans who was set free by Johnny McNicholl's inspired pass out of the back of his hand.

But Ulster's quality on the night was underlined when back-row Coetzee - who had been magnificent in defence - barged over for a fourth try to claim a precious bonus point.

Evans almost claimed his hat-trick try, but the wing was just bundled into touch by Louis Ludik and Speight.

Davies' last-gasp try for Scarlets, with Dan Jones adding a brilliant touchline conversion, set up a nervous finale but Ulster held out for the win.

A similar result over Scarlets at the Kingspan Stadium next Friday will put Ulster firmly back in the hunt for a place in the knock-out stage, before return fixtures with Leicester and Racing 92.

Scarlets may yet have a say in who goes through from Pool Four, but the remaining fixtures are now more likely to be about restoring hurt pride for last season's semi-finalists.

Ulster defence coach Jared Payne on BBC Radio Ulster: "The effort they put in tonight was just a really good performance, so huge credit to the guys for that. One big thing was the way we worked for each other right through the game.

"We were very clinical in the 22, which was great to see. It's not season-defining or anything like that, all it does is tick another box for us and it sets us up for the next week."

Scarlets head coach Wayne Pivac told BBC Radio Wales: "It was down to our own inaccuracy and in the first half it was probably defence; we fell off three tackles and they score from 60 metres, which was pretty soft.

"We did well to come back at the end there, but again we made a few line breaks and inaccuracy of the pass or catch sort of robbed us. We only have ourselves to blame.

"This is a low point... but it's not over, there are three games to go and we've got to keep building on our performances."

Scarlets: Johnny McNicholl; Tom Prydie, Jonathan Davies, Kieron Fonotia, Steff Evans; Rhys Patchell, Gareth Davies; Rob Evans, Ken Owens (capt), Samson Lee, Lewis Rawlins, David Bulbring, Will Boyde, James Davies, Uzair Cassiem

Replacements: Ryan Elias, Wyn Jones, Werner Kruger, Steve Cummins, Dan Davis, Sam Hidalgo-Clyne, Dan Jones, Hadleigh Parkes.

Ulster: L Ludik; H Speight, W Addison, S McCloskey, J Stockdale; B Burns, J Cooney; E O'Sullivan, R Best (capt), M Moore, I Henderson, K Treadwell, S Reidy, J Murphy, M Coetzee.

Replacements: R Herring, K McCall, T O'Toole, M Rea, N Timoney, D Shanahan, J McPhillips, D Cave.

Referee: Alexandre Ruiz (France)

Assistants: Ludovic Cayre (France), Cedric Marchat (France)

TMO: Eric Briquet-Campin (France)