Someone will crack, says Clermont's boss

The two best attacks still in the competition go face-to-face in Lyon and while Azema said they may try to play cagily, to begin with, someone will crack at some point and the two sides will go toe to toe.

"It's part of our DNA and it's part of their DNA," said Azema.

"Maybe there will be moments of observation where we'll both be trying to manage the game, but it's sure that at some point it will crack on one side or the other.

"There will be that desire to give everything to break the line and get an advantage,"

Leinster are the competition's top scorers with 35 tries in seven matches already, although Clermont are not far behind with 28 of their own - Wasps had scored 30 but were knocked out by Leinster in the last round.

When asked in what area Leinster are strongest, Azema said there were too many to count.

"There isn't one area in particular because they're a very structured team, playing very pragmatic rugby," said Azema.

"Everything is worked out and associated with their spirit: lots of ferocity and commitment on every area of the pitch and every aspect of the game.

"The line-out, perhaps, is a great platform to launch from, but they're also good at playing from inside their own half with an excellent kicking game, lots of commitment in the rucks, a very aggressive defence that pushes up high, almost inversely, and systematically looks to break the gainline.

"It's no surprise they're at this level,"

Leinster won the European Cup three times in four years from 2009 to 2012 but have not reached the final since.

Clermont were beaten finalists in 2013 and 2015, both times to Toulon.

Last season, both Clermont and Leinster finished bottom of their pools.

Agence France-Presse