Whatever we need to do to win we will do it vows centre ace Henshaw
What goes around comes around in this unforgiving game.
In November, when Robbie Henshaw's jaw met with Sam Cane's shoulder, the lights went out for a brief period.
Ireland's inside centre had been taken out in what was a fast-moving collision between two committed men.
Just under two weeks ago, it was Henshaw's shuddering hit that put England's Ben Te'o into the middle of this week.
First, there is the heat of the moment adrenalin rush of doing your job in a dramatic way which brings the crowd into the game.
"When you are able to put your body on the line for your side, that gives you some energy, gives the team some energy, well then, it is positive," he admitted. Then there is the human concern for a fellow warrior, in this case the man Henshaw replaced at Leinster.
"Obviously, it is not nice to see someone go down from a head-knock," said Henshaw.
"I was talking to Ben after and thankfully all was well, passed all his protocols.
"It is not a nice thing when two heads collide. That was completely unintentional."
Mostly, it is left for those outside the ring to throw the verbal punches that come in a blur, like the incidents themselves.
It is left to the players, and the people putting them back together, to pay the price for bravery.
First and foremost, rugby is a fight for ground attacked and defended, a fight for chances made and taken.
"It's knock-out rugby and whatever we need to do to win, we will do it," said Henshaw.
The modern day colosseum that is The Aviva will be close to sold-out and the battle will be guaranteed.
"Hearing there is 47,000 tickets-plus sold is unbelievable. "I think the atmosphere is going to be incredible.
"It is going to be two quality teams going hard at each other.
"For me personally, it is my first quarter-final in the Champions' Cup so it is all positive and it is all exciting."
Leinster and Wasps will take the two best attacks in the PRO12 and The Premiership to the European market place.
It could be a high-scoring shoot-out, the likes of which has not been seen at Lansdowne Road since Lawrence Dallaglio's London Wasps outplayed Munster 37-32 in the 2004 Heineken Cup semi-final.
Leinster will have to be at their best to overcome the club that twice dominated them last season.
"We are playing with a lot of confidence, our attacking game is quality. It's just about going out there and executing to the best of our ability."
The impact of Stuart Lancaster as defence coach has also led to ramped up intensity in line-speed.
"Our defence has to be world-class this week," said the Leinster centre.
"They have wheels on the edges, they have ball-players like (Danny) Cipriani and (Jimmy) Gopperth.
"We need to be fully ready and focused for what's coming at us."