A two-try second half performance drove Leinster to their first win on French soil since October 2014 as they advanced to the Champions Cup quarter-finals as top seeds.

Leo Cullen’s men needed just a single point to secure that number one seeding, but pocketed four at the Altrad Stadium as they made it a clean sweep of Pool 3 victories – the first time the province have won six-out-of-six in Europe since the 2004/05 season.

Ross Byrne’s first senior try capped off a strong first quarter from Leinster, but some powerful close-in lineouts allowed Montpellier back into it. Tries from Bismarck du Plessis and Yacouba Camara handed the Top 14 leaders a 14-8 half-time lead.

However, with their pack getting on top, the visitors produced a tremendous third quarter which saw Robbie Henshaw and man-of-the-match Sean Cronin both cross the whitewash and Byrne complete his 13-point tally. The excellent Henshaw spearheaded a determined defensive display that ensured Montpellier were held scoreless during the entire the second half.

Although the home side were quick out of the blocks, Leinster, who had already booked a Dublin quarter-final, hit the front in the fourth minute thanks to some slick approach play by James Lowe, who linked neatly with Jamison Gibson-Park before bursting up close to the try-line. The winger ensured quick ruck ball under pressure from three defenders, and Gibson-Park’s pass put the waiting Byrne over in the left corner. The out-half was unable to convert.

Leinster’s impressive retention of possession, coupled with out-half Byrne’s clever kicking behind the wingers, kept them in control, but Konstantine Mikautadze’s maul turnover almost led to a breakaway try for the hosts, with Timoci Nagusa’s scoring pass to Ruan Pienaar going forward.

Lowe popped up on the opposite wing to cause further damage, offloading for Josh van der Flier to gobble up the metres and set up a 19th minute penalty which Byrne rifled over for an 8-0 lead.

Nonetheless, a misplaced Lowe pass allowed Montpellier to build from a lineout, before Frans Steyn and Nagusa were thwarted on the right wing. The hosts had earned a penalty on the opposite flank and they backed their powerful maul to deliver, with hooker du Plessis duly diving over and Aaron Cruden’s touchline conversion suddenly made it a one-point game.

It was a worrying spell for Leinster with Lowe intercepted by Nemani Nadolo and Cruden then making a break, but James Ryan and Rob Kearney did well to tidy up on both occasions, the latter clearing his lines from a Pienaar kick in behind.

Frustratingly, the errors kept coming from Leinster who had missed 13 tackles by the interval. The otherwise impressive Henshaw threw a forward pass and Tadhg Furlong played the ball on the ground, a few phases later, as Montpellier ominously worked their way into scoring range again.

From the subsequent lineout, the French side opted against the maul as Nicholaas van Rensburg combined with captain Louis Picamoles who attacked some space at the rear and fed flanker Camara for a well-finished score, converted by Cruden.

Replays showed Mikheil Nariashvili had obstructed Cian Healy in defence, helping to open up the gap for Picamoles, but the try stood and Leinster had to scramble to avoid another concession before half-time. It was Furlong who brought down Nadolo to prevent a almost certain try, with van der Flier completing a much-needed turnover.

The half-time break came at a good time for Leinster, who resumed in much better fettle, attacking hard through their forwards with Sean Cronin particularly prominent as a carrier and showing good footwork.

Jordan Larmour also increased his threat with ball in hand as Cullen’s charges won successive penalties near the try-line, turning down the place-kick and forcing Montpellier to defend a series of high-tempo phases. Crisp passes from Gibson-Park and Kearney eventually saw Henshaw step inside Nadolo to touch down in the right corner.

Byrne missed the conversion but nailed a close-range 49th-minute penalty, rewarding van der Flier for some excellent work in defence which forced a turnover and had Montpellier scrambling back into their 22.

Leinster struck a significant blow just two minutes later, Cronin returning the favour by diving over from a robust lineout maul with Byrne converting. Lovely hands from Cronin, Ryan and Dan Leavy had set the wheels in motion, Gibson-Park’s kick chase then forcing the lineout from which the visitors moved 23-14 ahead.

Larmour’s important tackle on Nadolo, which saw him climb over the back of the Fijian powerhouse, prevented Montpellier from building momentum, and the 20-year-old also pressed high following a Luke McGrath clearance kick to win turnover ball. A bonus point score was on the cards as replacement McGrath went close from a neat lineout move, but just as the forwards edged closer, Yvan Watremez won a relieving penalty at the breakdown.

The final 10 minutes saw Montpellier look for a grandstand finish as they were still in contention for a quarter-final spot. There was no repeat of their first half maul tries, though, as Jordi Murphy disrupted and conceded a penalty at their first effort in the 69th minute, and Devin Toner stole the next lineout, five metres out from his own whitewash.

Replacements Jack McGrath and Andrew Porter combined to win a penalty at the breakdown, on the Leinster 10-metre line, and although Montpellier managed to end the game on the front foot and attacking out wide, Leinster shut down their late try-scoring attempts. The sight of Joey Carbery returning from injury was another positive to take from a rewarding afternoon in the south of France.

Leinster are back in the RDS Arena on 17th February to take on Scarlets in a crucial Guinness PRO14 Conference B clash. Join the roar and get tickets now.

Leinster v Scarlets