Blues dig out Scarlets scalp
Leinster 19 Scarlets 15
Leo Cullen does not select out of the pressure to win, but out of the frame of mind of what is right or wrong.
So someone who knows him far better than yours truly said on Thursday night.
That is the reason Garry Ringrose, Cian Kelleher and James Tracy were pitched into the deep end of the PRO12 Pool last night. They earned their right of reply at training and in competition.
The Scarlets arrived into The RDS with a perfect record from the first six rounds.
The Welsh got straight down to business, launching a quick raid in a show of confidence. Dominic Ryan's ill-advised swipe invited pressure and centre Hadleigh Parkes powered through Noel Reid for a try at the posts, converted by fly-half Dan Jones.
A stunning Leinster maul forced a yellow card for Jake Ball before Isaac Boss went close, Ian Madigan making it 7-3 in the 12th minute.
There followed a period of play where Scarlets took no prisoners and Leinster no points.
Hooker Emyr Phillips was lucky to escape with no greater punishment than a penalty when he took out Madigan at a ruck.
The victim took solace from his three points.
The league leaders were slick, making their move into the left corner where centre Gareth Owen slid past Madigan, just after Ben Te'o had been introduced for Rob Kearney - with the Ireland fullback appearing to pull a hamstring.
Once again, Leinster took this on the chin for Madigan to rifle a penalty quickly countered by Jones for a ruck infraction, making it 15-9 to the Welsh.
The lineout was out of kilter, although Tracy did come to the rescue at a ruck.
Despite Ringrose almost turning nothing into something from Madigan's hack ahead, it could have been even worse for the home side at half-time had Jones not pulled his shot left of the uprights.
Leinster had to go back to basics. Win the ball. Use it cleverly. Madigan pinged a penalty to the corner. Devin Toner took in the lineout. The drives came.
Mike Ross was the unlikely hero from about one metre out. Madigan's two put Leinster one in front in the 45th minute.
The pressure Jamie Heaslip put on Gareth Davies gave Leinster prime location ahead of the return of Johnny Sexton in the 52nd minute.
A no-arms tackle by Ball could have cost him a second yellow, upgraded to a red. Instead, he was shown mercy by referee Leighton Hodges.
The Scarlets were flirting with the offside line all night. They eventually coughed up three to Madigan for that indiscretion on the hour.
Sexton was denied a storybook try by Noel Reid's obstruction on centre Owen.
The biggest impact came from two flashing tackles by Hayden Triggs to turn Scarlets back and Dan Leavy's bone-rattler on Maselino Paulino to close it out.
It took Leinster level on points with Munster and removed The Scarlets unbeaten start to the season.
Not a bad night's work.