Leo Cullen has warned his Leinster players not to get on referee Wayne Barnes' wrong side in Sunday's European Champions Cup semi-final meeting with Toulon in Marseille.
The English official has been a controversial figure in Irish circles since his performance during Ireland's defeat to Wales during the Six Nations, when he was criticised by the national team set-up for his inconsistent decisions at the breakdown and for his interpretations at a vital last scrum when Joe Schmidt's men were chasing the game.
One noticeable factor at the Millennium Stadium was how Ireland's players' protestations wore on Barnes' patience as the game went on, with Leinster flanker Sean O'Brien warned to stop talking to him.
The experienced referee took charge of Leinster's last two knockout games in France, the loss to Toulon in last year's quarter-final and the 2012 semi-final victory over Clermont Auvergne in Bordeaux.
Having played in both of those games, forwards coach Cullen says that Leinster are fully aware of what the official expects.
"Wayne Barnes is an incredibly experienced referee and I think you can see from the way he reffed later in the Six Nations," Cullen said. "He was pretty hard on guys in the back of tackles.
"We've encountered each other on numerous occasions. He's one of the top referees in the world, if not the top, so hopefully he'll have a pretty good handle on the way they (Toulon) are.
"We drove our discipline really hard in the Bath week and you can see the results - we gave four penalties away in the game.
"That's really important in these play-off games. There's such fine margins. So we need to make sure we're squeaky clean. We're not trying to con the referee, we're trying to paint good pictures all the time, and chatting back to a referee is not something that we push.
"We need to make sure that if that is the case, guys have learned those lessons, and they're dealing with whoever is captain on the day."
Meanwhile, Toulon have included Wales full-back Leigh Halfpenny in their 29-man squad for Sunday's game. The Lion remains a doubt after suffering a minor shoulder dislocation.
Toulon squad for Leinster: Forwards: X Chiocci, A Menini, F Fresia, JC Orioli, G Guirado, C Burden, C Hayman, L Chilachava, M Castrogiovanni, J Suta, R Taofifenua, A Williams, B Botha, M Gorgodze, C Masoe, J Smith, S Armitage, J Fernandez Lobbe; Backs: S Tillous-Borde, M Claasens, E Escande, F Michalak, M Giteau, R Wulf, M BAstareaud, D Mitchell, L Halfpenny, B Habana, D Armitage.