Leinster combined incisive attack with steadfast defence to score seven tries and thrash Northampton Saints as they took control of Pool 1 of the Heineken Champions Cup.

Leo Cullen's side led 19-16 at half-time of a thrilling contest, having outscored the hosts three tries to one but conceded a string of kickable penalties that Dan Biggar converted.

James Lowe and Jordan Larmour were cutting the Saints defence to shreds and Lowe, Rhys Ruddock and Andrew Porter all touched down.

Leinster's defence was superb after the restart, led by Josh van der Flier, and they held Northampton scoreless in the second half while running in further tries from Ross Byrne, Cian Healy, Luke McGrath and Ed Byrne.

The only downside on the day was the sight of captain Johnny Sexton limping off with a knee injury early in the second half, which must make him a doubt for the return fixture at the RDS next weekend.

Premiership leaders Northampton had been superb until colliding with Leinster, catching the eye with an attacking style that was matched by results in the form of six wins from seven outings.

But they were taught a lesson in European rugby by the four-time champions who fielded greater firepower in most departments and who were able to call on a watertight defence to contain Northampton's assault in the final half-hour.

It took only 131 seconds for Leinster to draw first blood as they pounced on a Northampton mistake in midfield with full-back Larmour tearing downfield before sending James Lowe over.

Clean line-out ball enabled Saints to respond as Ahsee Tuala and Teimana Harrison made big carries through the middle and, when the move swept left, quick hands ended with Tuala diving over in the right corner.

Larmour's scorching start continued as he took Sexton's clever inside ball and stepped his way into space, offering scrum-half Jamison Gibson-Park sight of the line only for Cobus Reinach to capitalise on a moment's hesitation with a covering tackle.

Leinster were not to be denied however and, after several surges, Rhys Ruddock forced his way over.
Dan Biggar's accuracy from the kicking tee, combined with his cunning break-up field, helped Northampton regain the lead against the run of play - but they were unable to score again.

Josh van der Flier starred for Leinster

After a bright spell from Saints, when they profited from being more direct, Leinster built pressure once more and their power from close range was irresistible as prop Andrew Porter burrowed a path through the home pack.

The second-half opened with another searing run from Larmour and his injection of pace was the prelude to waves of forward carries that ended when Cian Healy touched down.

It was the worst possible start to the second-half for Saints and they were in danger of being blown away as the European heavyweights immediately renewed their attack through Garry Ringrose and Robbie Henshaw.

This time Ross Byrne was on hand to finish and to compound home misery co-captain Alex Waller was sent to the sin-bin for a shove from behind moments before the try was scored.

Sexton's exit failed to affect Irish momentum but a setback did arrive in the form of a yellow card for Ringrose for his tip-tackle on Biggar, who had recovered from a toe injury to take his place at fly-half.

Leinster's defence held firm as Northampton cranked up the intensity but a series of handling errors at key moments proved costly, while even giant wing Taqele Naiyaravoro was unable to make any impression.

Ireland lock James Ryan limped off but it made no odds as additional blows were landed when replacements Luke McGrath and Ed Byrne touched down.

Elsewhere in Pool 1, Lyon secured their first-ever Champions Cup victory with a 28-0 home win over Benetton.

The French Top 14 side broke their duck at the ninth attempt and also registered a late bonus point.

Full-back Jean-Marcellin Buttin opened the scoring in the third minute and New Zealander Charlie Ngatai soon crossed for Jonathan Wisniewski to convert.

Wisniewski's penalty put Lyon into a 15-0 lead before wing Xavier Mignot dotted down 12 minutes from half-time.

The Italian visitors were reduced to 14 men when replacement Marco Barbini was yellow carded and a Pato Fernandez penalty extended Lyon's lead.

Lyon's fourth try came five minutes from time when a driving line-out drew in the Benetton defence and replacement Liam Gill dived over in the corner.