Sexton scored a try, a conversion and five penalties and helped Leinster break clear of the Scarlets and record their eleventh straight victory at their Dublin base.

But fellow Ireland hopeful Sean O’Brien saw his night ended early through injury, hampering the No.8’s chances of being selected for Saturday’s RBS 6 Nations clash with England. .

The Scarlets will be disappointed with the result as they failed to make the most of some excellent try-scoring opportunities, the most noteworthy seeing Rob McCusker knock on after blocking Shaun Berne’s 70th-minute clearance.

Jonathan Davies and the fit-again Regan King started well for the visitors but Sexton converted a penalty to open the scoring.

Davies rumbled forward to set up Rhys Priestland for a levelling penalty and the Scarlets surged 8-3 ahead just a minute later.

Leinster were caught napping following a long range Scarlets break and hooker Ken Owens finished off in the left corner.

Priestland failed to add the extras and Leinster’s Nacewa crossed the line shortly after.

Sexton nailed the conversion from close to the touchline and swapped further penalties with Priestland as Leinster went in at the break 13-11 ahead.

Scarlets fly-half Priestland kicked his side back into the lead shortly after the break but Sexton added three well-struck penalties on 48, 57 and 67 minutes to turn the tide again.

Sexton then collected a pass from debutant Andrew Conway to score the clinching try, four minutes from time.