Unbeaten United Rugby Championship leaders Leinster extended their advantage at the top of the table with victory at sorry Scarlets.

Scarlets only managed a first-half try through centre Steff Evans.

The pressure is mounting on Scarlets head coach Dwayne Peel, who has overseen only one victory in the opening block of seven matches.

Scarlets have lost five, drawn one and claimed a solitary victory against bottom side Zebre.

The concerning thing is five out of the first seven games have been at Parc y Scarlets, with only four home league matches remaining this season.

Indiscipline has been a common theme, with Scarlets suffering three more sin-bins against Leinster, who now lead Ulster by 12 points in the standings.

That takes the total to nine yellow cards and two reds in the opening seven games of the season.

A misfiring line-out and lacklustre attack were also worrying factors of this insipid display against Leinster.

Scarlets now have a month's break to lick their wounds before the unenviable task of travelling to South Africa for two away games against Stormers and Lions.

Fifty years ago Llanelli famously defeated the All Blacks but there was no air of celebration at Parc y Scarlets to mark the occasion.

Shadow sides

Both sides were shorn of a number of players because of injuries and international commitments but Leinster demonstrated the greater strength in depth.

Leinster made 11 changes, including the return of skipper Rhys Ruddock, with the Irish province having 17 players named in the initial national squad.

Scarlets' unavailability list, which included suspension and injury and international commitments, was more than 20.

They included the suspended duo Sam Lousi and Vaea Fifita and injured players Wyn Jones, Scott Williams, Blade Thomson, Johnny Williams, Ioan Nicholas, Tomás Lezana, Phil Price, Lewis Rawlins, Joe Roberts, Carwyn Tuipulotu, Callum Williams, Samson Lee and Griff Evans.

Ken Owens, Ryan Elias, Josh Macleod, Sam Costelow, Dane Blacker, Leigh Halfpenny and Kieran Hardy were away on international duty.

Scarlets did welcome back Wales duo Aaron Shingler and Tom Rogers, while scrum-half Gareth Davies returned after being left out by Wales. Fly-half Dan Jones and hooker Daf Hughes also started.

Scarlets suffered a disastrous start as they conceded a try inside 40 seconds. After Shingler failed to gain the kick-off, Leinster took advantage with a simple well-worked try from a line-out for full-back Cosgrave to cross, with Ross Byrne converting.

Scarlets responded with a try for centre Evans, who was the beneficiary of a long pass from captain Jonathan Davies.

Leinster's second try was scored by wing Russell after he followed up his own kick.

Hooker John McKee helped create the score after battling for possession, with the ball fortuitously coming off his head before Russell touched down as the visitors led 14-5 at half-time.

Scarlets' line-out continued to malfunction in the second half while, in contrast, Leinster's set-piece effectively led to a third try for prop Clarkson following a clinical drive.

The home side finally showed some counter-attacking intent through Johnny McNicholl and Ryan Conbeer, with only Cosgrave denying Evans a spectacular length-of-the-field try.

Scarlets' indiscipline continued as the hosts were reduced to 13 men within a minute as fly-half Dan Jones and McNicholl were shown yellow cards.

Jones was sanctioned for persistent offside offences, while McNicholl's deliberate knock-on yielded a penalty try which brought up the bonus-point score for Leinster.

Replacement Leinster prop Michael Milne was shown a yellow card, but Gareth Davies became the latest Scarlets' player to be sent to the sin-bin for a professional foul as Leinster scored a second penalty try.

It completed another horrendous evening for Peel and Scarlets, who languish in 15th place with only Zebre below them.

Scarlets head coach Dwayne Peel: "We spoke to the group and before the game we asked them to upset the rhythm against Leinster, and for large parts physicality-wise we were good.

"I think we were 10 line-breaks to three in our favour. Inaccuracy at times cost us. We got behind them but did not finish, we had a couple of set-piece errors as well.

"Some inaccuracy led to pressure and led to penalties. We need to be better in our discipline and we have a couple of weeks to reflect and work on that.

"From an effort perspective, I thought we were pretty good and Leinster would probably have thought our physicality was good. We were inaccurate and they were accurate which is what makes them the team they are."

Leinster captain Rhys Ruddock: "We are delighted. We knew it would be a real challenge coming here. We knew Scarlets would throw everything at us and they certainly did.

"We probably lacked a bit of clinical finishing in the first half but we are happy with the performance overall."

Scarlets: Johnny McNicholl; Tom Rogers, Steff Evans, Jonathan Davies (capt), Ryan Conbeer; Dan Jones, Gareth Davies; Steff Thomas, Daf Hughes, Harri O'Connor, Jac Price, Tom Price, Aaron Shingler, Dan Thomas, Sione Kalamafoni.

Replacements: Shaun Evans, Kemsley Mathias, WillGriff John, Morgan Jones, Iwan Shenton, Archie Hughes, Rhys Patchell, Corey Baldwin.

Leinster: Chris Cosgrave; Rob Russell, Liam Turner, Charlie Ngatai, Dave Kearney; Ross Byrne, Luke McGrath; Ed Byrne, John McKee, Thomas Clarkson, Ross Molony, Jason Jenkins, Rhys Ruddock (capt), Scott Penny, Max Deegan.

Replacements: Tadgh McElroy, Michael Milne, Vakhtang Abdaladze, Brian Deeny, Martin Moloney, Nick McCarthy, Charlie Tector, Ben Brownlee

Referee: Andrea Piardi (FIR)

Assistant referees: Adam Jones & Simon Mills (WRU)

TMO: Matteo Liperini (FIR)