Leinster are rumbling...

Devin Toner crashes into the Clermont 22m.

A try so soon into the second half would get the gremlins nibbling at Clermont's nerves.

Penalty advantage Leinster!

Back up and running in Lyon.

The kick-off is safely gathered by Isa Nacewa and Leinster keep the ball in hand and try and play their way out from deep rather than put boot to ball.

Will they try and run the legs off Clermont and reap the benefits late on?

The half-time stats are in.

Clermont are well worth their lead.

Clermont-Leinster

Possession: 56%-43%

Territory: 60%-40%

Metres made: 215-239

Clean breaks: 6-1

Tackles made/missed: 46/13 - 74/10

Image source, Getty Images

John McEnerney: We've comeback from worse remember the 2011 final Sexton ran the second half then, it's not beyond Leinster just yet  

Leinster's bench is packed with players who revel in the wide open spaces,

Hooker Sean Cronin and flanker Josh van der Flier might be strong picks on the hour mark for Leo Cullen, if not before.

Zane Kirchner is also riding the pine for Leinster.

Image source, Rex Features

Johnny Sexton's kick sails through the sticks and the two teams disappear down the tunnel for half-time.

All to do for Leinster.

Nigel Owens peeps the whistle as the Clermont forwards come off their feet.

With the clock deep in the red, there is no time to go for the corner.

Sexton opts for what should be a straightforward three points with the last play of the half.

Up to the Clermont 22m line...

Leinster are pressing and probing as they attempt to finish a bum first half on a high note.

Rhys Ruddock charges over the Clermont 10m line. Multi phases and the French defence is looking patchy...

Morgan Parra sends a scruffy effort wide of the posts. That will be a relief for Leo Cullen as he prepares to rally his troops with the mother of all half-time pep talks.

Image source, Rex Features

Clermont are awarded a penalty as Rhys Ruddock goes too high on Morgan Parra. The Clermont scrum-half was ducking and diving though so it is not yellow card material.

It is a kickable penalty though....

Leinster manage to win a line-out. Which is a start.

But scrum-half Luke McGrath is under a whole heap of pressure as Peceli Yato bears down on him.

Johnny Sexton puts the ball to ground out wide. Clermont hack upfield and Scott Spedding is a despairing Joey Carbery tackle away from going in after scooping the ball up on the chase.

Image source, Getty Images

Better from Leinster.

They move the ball with more pace and precision out wide. Isa Nacewa makes gains down their left.

But things are still not quite clicking.

Fergus McFadden chops his attempted chip out on the full. An ugly kick and an eyesore of a scoreline for the visitors.

David Strettle - who has had a stellar opening 25 minutes - claims a cross-field bomb from Johnny Sexton and flicks the pass inside to Benjamin Kayser.

A knock-forward from Clermont. But all the invention and industry is coming from the French side.

Leinster are on the ropes and halfway to the floor. They could do with the half-time bell. It is still 13 minutes away.

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Turnover! Space! Counter!

Leinster stream wide and forward, like the Red Arrows. 

Garry Ringrose steps inside, ships outside and there is a man over...

Nope. David Strettle covers across the pitch like a gale and dislodges the ball out of Joey Carbery's grasp.

Great tackle.

Some seismic collisions out there.

Leinster number eight Jack Conan shrugs off Damien Chouly as the France international comes rushing out of the line after Rhys Ruddock bounces through a couple of tacklers.

But Clermont are doing the dirty unseen stuff as well as the showreel hits. Fritz Lee clamps down over the tackled man to secure another turnover and his team are back down into the Leinster 22m.

If the next try is Clermont's, you might as well start reading the rites on this one...

Clermont are pouring energy and manpower into the breakdown and they are being rewarded with a steady stream of penalties and turnovers.

Clermont claim a line-out on the Leinster 22m and the Irish are under pressure once again.

With less than a quarter of the match gone, Leinster have sprung a 15-point hole.

Devin Toner gets into a little dust-up on the floor. "Calm it Morgan, calm it," says ref Nigel Owens to the Clermont scrum-half as he comes yapping up at the big second row's ankles.

The French national anthem is ringing around the stands. Isa Nacewa comes back into the fray to even up the teams after his yellow card.