Clermont Auvergne 15 Leinster 12:Leinster's 17-match unbeaten run was ended at the Stade Marcel Michelin as Vern Cotter's French side gained a measure of revenge for defeat in last year's Heineken Cup semi-final.
Leinster’s last loss in the competition had come at Clermont back in 2010 before they embarked on a run that included tournament victories in 2011 and 2012.
In a bruising affair, the scoring all came from the boot, with Morgan Parra and Jonny Sexton kicking four penalties apiece, while Brock James dropped a vital goal just before the interval to give the home side a 15-9 lead at the break.
Sexton was successful with the only score of the second half when he landed a penalty in the 54rd minute, but despite some long periods of possession, Leinster could not make the breakthrough they needed to earn a win or draw as Clermont extended their unbeaten run at home to an amazing 51 games.
Leinster’s bonus point means they now trail Clermont by five points ahead of next Saturday’s return fixture at the Aviva Stadium.
Seán O’Brien had an impressive return to European action in a barnstorming backrow unit, with Fergus McFadden and cup debutant Andrew Goodman the pick of the visitors’ backs.
There was a raucous atmosphere in Clermont’s home fortress and they drew first blood, Parra popping over a penalty from in front of the posts but Leinster carried more of an early threat with ball in hand.
Jamie Heaslip’s inside pass put Ian Madigan through a midfield hole and Sexton stepped up to convert the subsequent penalty.
An obstruction from a lineout went unpunished as Sexton missed a tricky penalty, with play swinging back and forth at a hectic pace.
A strong burst from Napolioni Nalaga led to Parra kicking Clermont back in front by the end of a defence-dominated first quarter.
The home side cranked it up as Sitiveni Sivivatu drew in two defenders, releasing Aurelien Rougerie and Lee Byrne for a right-wing surge that almost led to a try.
A third successful penalty from Parra stretched the margin to 9-3, but Leinster were quick to respond through a bout of sturdy carries from McFadden, Cian Healy and Kevin McLaughlin.
Sexton was back on target with a penalty from the 22 and as the Leinster pack exerted more control, they continued to make good ground.
Madigan burst into the 22 and with Clermont penalised for not rolling away, Sexton brought the title holders level.
However, Clermont hit back through another penalty from Parra and James’s late drop goal put six points between the sides at the break.
Sexton and Madigan probed with clever kicks on the resumption, while Isa Nacewa and McFadden both went close to collecting cross-field kicks from the Leinster number 10. Wales and Lions full-back Byrne did brilliantly to deny the former.
After two confidence-boosting scrums, with Mike Ross shunting Vincent Debaty backwards, Sexton slotted his fourth successful penalty with 54 minutes on the clock.
Clermont looked to be tiring but Byrne did well again to sweep the ball into touch with Nacewa bearing down on him as he chased Gordon D’Arcy’s kick.
Although the French outfit responded with two side-stepping runs from the dangerous Wesley Fofana, Leinster defended stoutly but a couple of loose lineouts - with replacement hooker Richard Strauss on the pitch - robbed them of promising attacking positions as time ran down.
