48,964 spectators - an Irish record for a European pool match - watched Wesley Fofana tear over for a try six minutes before the break to help Clermont push 16-6 clear.

Man-of-the-match Parra managed to convert Fofana's try, adding to three earlier penalties, with Jonathan Sexton booting a brace of penalties for Joe Schmidt's charges.

As Leinster continued to leak penalties, Parra's left boot kept Clermont on course to end a run of five successive defeats in Ireland since 2007.

The margin was widened to 25-9 before Leinster recovered to score two tries in the closing quarter hour through Shane Jennings and Fergus McFadden, the latter's effort coming from a daring 78th minute raid.

McFadden's try garnered a losing bonus point for a well-beaten Leinster side, who are now eight points adrift of Pool 5 leaders Clermont with third-placed Exeter Chiefs nipping at their heels.

Leinster had only scored one try in their previous three pool games and with Clermont opening up a five-point lead at the top of the table, a home win was simply a must.

Eoin Reddan, Heinke van der Merwe, Richardt Strauss and Jennings were promoted to the province's starting line-up following last Sunday's bruising 15-12 defeat in Clermont.

The visitors drafted in prop Raphael Chaume and flanker Julien Bardy, while their Australian number 10 Brock James passed a late fitness test on a groin complaint.

James said earlier this week that they had 'learned the lessons' of past defeats in Dublin, including a quarter-final exit in April 2010 and a deflating 24-8 loss the following December at this same venue.

There was real evidence of that here as hard-hitting Clermont helped themselves to 10 unanswered points closing in on half-time, silencing the home crowd with Fofana's sucker punch score.

The rugby was typically fast and frantic early on with Leinster seizing upon two turnovers and Sexton running smartly to almost link up with hooker Strauss.

Damien Chouly and Napolioni Nalaga carried well before Clermont won a left-sided penalty that Parra poked through the uprights for a seventh minute lead.

Four minutes later, Leinster lost Strauss to injury as Clermont confidently went about their business with James' pinpoint kicks forcing a couple of spills from Ian Madigan.

Sexton and Parra swapped penalties at the end of the first quarter, the France scrum half replying almost immediately as Jamie Heaslip came in at the side of a ruck.

The tempo was lifted by the hosts under Sexton's baton, courtesy of a muscular turnover in midfield and pressure from Mike Ross on Chaume in the scrum.

A second three-pointer from Sexton brought Leinster level again, but Clermont were well organised in defence and were quick to counter when offered space.

A loose Madigan kick invited Davit Zirakashvili to hurtle forward into contact, setting up a power-packed attack that led to Fofana probing in the right corner.

James' tactical kicking was right on the money, giving his side plenty of targets and Clermont really came to the boil before half-time with Parra's third penalty moving them back ahead.

Sitiveni Sivivatu then sparked a three-man surge down the left. Nalaga was chopped down short of the try-line but Fofana proved unstoppable as he darted onto quick ruck ball to dot down from close range.

Parra's terrific conversion increased the pressure on Leinster who looked flat at times, leaking a series of costly penalties. Another indiscretion - this time Ross infringed in a scrum - allowed Parra to fire over the first points of the second half, his kick bending in from right to left.

Sexton cancelled that score out as Leinster mounted a strong response, with replacement Cian Healy being part of a penalty-winning scrum on halfway. However, Sexton was unable to convert the resulting 50-metre kick.

After the wily Parra took a quick tap, Sean O'Brien's early challenge on Sivivatu earned him a yellow card. Leinster's day darkened further as Parra nailed the penalty for 22-9.

Vern Cotter's men really had the bit between their teeth now, hammering home their numerical advantage up front. Captain Aurelien Rougerie and Nalaga both went close to scoring a try that would have sewn up the result.

Ross was replaced as Leinster's scrum gave way, and Parra potted a 32-metre penalty having struck the woodwork with an attempt from the right four minutes earlier.

Clermont had a foot on Leinster's throat, but the champions showed their quality as Sexton kicked a penalty to touch, Devin Toner won the close-in lineout at the front and a muscular maul led to flanker Jennings plunging over for a 65th minute try.

Sexton's conversion closed the gap to nine points. However, the imperious Parra replied by landing his final penalty to punish Healy for not rolling away.

Clermont lost their openside Bardy to the sin-bin for the final six minutes and a late defensive lapse saw Leinster break out of their half through O'Brien and Sexton, with the out-half delaying his pass neatly for McFadden to score in the right corner.

The conversion was missed and there was no denying Clermont a long-awaited maiden win on Irish soil, their upsetting of the champions being as much about their mental toughness as their physically imposing play up front.