The Scarlets opened their Magners League campaign with a narrow 18-16 victory over Heineken Cup champions Leinster at Parc y Scarlets.

Tries from Sean Lamont and Phil John kept the Scarlets in a match they seemed destined to lose before Rhys Priestland gave his side the lead with a 71st minute penalty.

And Leinster, minus six British Lions including Brian O'Driscoll, must have wondered how they lost a game they dominated in both possession and territory.

New signing Lamont grabbed the first try of the Scarlets' new season after just six minutes.

Leinster made amends on 19 minutes as Girvan Dempsey went in down the right after pressure had developed an overlap.

The visitors' lead increased from 10-7 to 16-7 with two more Sexton penalties, the second coming after Richie Pugh was sin-binned for using his hands in a ruck.

Four minutes later the Scarlets were down to 13 men after suffering a second yellow card when Rhys Thomas was sent to the cooler for dangerous play at a ruck.

Twelve minutes into the second half the Irishmen thought they had scored their second try when Shane Jennings appeared to get the ball down on the line, but the TV match official ruled it out.

Against the run of play it was the Scarlets who registered the first score of the second half after 25 minutes. Jonathan Davies made the initial break into the Leinster half before Mark Jones put replacement prop John over.

In injury time Priestland was wide with a drop-goal attempt which added pressure to the Scarlets' victory charge.