Return of Sexton is key to success for Blues
Leo Cullen has been forewarned. Will he be forearmed?
Leinster got out of the blocks like an age old pensioner against The Scarlets in the PRO12 last Saturday and against Wasps in The Champions Cup last season.
The pain of conceding early and easy ground is not something you want to have to recover from.
"We had a soft start against Wasps last year in The RDS. We were 20 points-to-eight down and made life very, very difficult for ourselves," recalled Cullen.
This is where Jonathan Sexton comes into the picture as something of a saviour and ambassador for the 'Leinster Way'.
The all-court advantages he can activate are well-known and even better executed.
This is why Sexton was brought back, to turn the strength of Wasps back three, most likely to be Charles Piutau, Frank Halai and Christian Wade, into a weakness.
The variation to his kicking game and the scanning eyes are expert at spotting space and moving into it whether it is a long, raking ball forward or a whipping passing game.
For all of that to happen, Leinster will have to find traction up front where they have the front row resources to match-up against any club in Europe.
Who would have thought that the case seven or eight years ago?
The back-five forwards will have a real job of work on their hands.
However, there must be a question mark over the apparent knockout blows taken by Wales lock Bradley Davies and number eight Nathan Hughes against Gloucester last Sunday.
They were clearly concussed and allowed to return to the field of play following Head Injury Assessments.
Wasps will come with the confidence to sting Leinster.
When Dai Young's club is out for blood, James Haskell is often front and centre of the argument, verbal and physical.
"It will be a big test, but if you want to win the Champions Cup, you have to go and beat the best," he said.
"That's what we want to do as a side. We've developed a team with top players across the board and a really settled coaching staff.
"It's now just about getting that performance on the field and the players are responsible for that."
It is not so much Haskell, the bulwark, as Wade, the rapier, which has exposed Leinster in the past.
Wing Wade is a wonder in, or even out of, space as he showed with wonder tries against Leinster in the 2013 Challenge Cup quarter-final and in the round one Pool match of The Champions Cup at The RDS last year.
The sight of Leinster's blue jersey must be enough to send Wade's confidence sky-high.
"We really want to play to our potential and try to make everything click, after going so close in the two games against them last season," he said.
"We are definitely going out there with the intention of putting in a performance and coming away with the win.
"Of course, that will not be an easy task," he added.
"You only have to look at the quality they have and the calibre of the players coming back after the World Cup."
It will be explosive. From the start.
Leinster v Wasps, The RDS, Sunday (KO 1.00pm, BT Sport Europe)