Finally, Leinster show their true selves. Maybe it was the return of Fergus McFadden or the superb showing by Jordi Murphy or just a collective bloody-mindedness that had the ineffective French visitors flipped and emptied by half-time.

"Yeah, definitely," agreed Matt O'Connor. "But in saying that, we weren't as accurate with the ball in the first-half as we would have liked. I think we turned it over 10 times. That certainly won't be good enough next week against Wasps. "

Also true. But the point holds. Leinster continually refused three-point opportunities to instead pursue the bonus-point try that puts them in control of their own destiny.

However, the tactics for Wasps will need to be radically different. On-the-road-cup-rugby is next but they know how to do that as well.

European oxygen

It also helps that the weight caused by a chronic injury list is beginning to lift.

They are the only Irish province still breathing European oxygen. The grumblers, whose din had been growing since November, have been silenced for now.

A packed RDS was treated to a bonus point by half-time thanks mainly to Ibrahim Diarra's sin-binning, which had been coming – Castres were spoiling on an epidemic scale, as maybe, just maybe, we witnessed the real dawn of this new look Leinster.

There was no Mike Ross on the team sheet – not injured either – as Marty Moore shuttled around the Ballsbridge paddock, claiming the second try on 27 minutes off a lineout maul.

That was the third foray, with refreshing directness, into Castres’ 22 since Dave Kearney’s defence splitting try with just 2.51 on the clock. All but one three-pointer was rejected by captain Jamie Heaslip as the intent that had been missing all campaign was finally evident.

“It is certainly the most intent we have gone into a game this season in terms of putting the opposition under pressure with ball in play and ball in hand and we got the reward for that,” O’Connor went on.

“Maybe there is a learning in it for us. Given the confidence that we have built and the combinations that we have got, moving forward, there is no reason why we cannot have that intent every week.”

Devin Toner's lineout was a crucial cog in their offence, with Jimmy Gopperth feeding Ian Madigan, who reversed play to allow Kearney to sprint away.

Double movement

Handling errors, with Madigan and Kearney guilty in sight of the line, meant the game was in the balance until Moore was mauled over. Then they settled. Still, a slight reprieve should have come Castres way but referee Marius Mitrea denied Marcel Garvey a try down the other end. The English winger ran over Madigan but was adjudged to have made a double movement. He didn’t

Nor did Eoin Reddan when he picked up where Murphy was just stopped short for try number three. Madigan nailed the conversion, as Diarra returned to a 24-3 scoreboard.

The assault continued with Sean Cronin – Leinster’s best player this season – darting over after Toner, Heaslip (twice) and many more hands dazzled the gallery. It was almost like when Dr Contepomi, O’Driscoll and Hickie tip-toed across these very boards. Almost.

Madigan nailed another conversion and the pitch emptied to polite applause. The RDS supporters were refined until they pilloried Richie Gray for rattling McFadden late on. Mitrea went to the TMO to reveal very little took place. The touch judges really don't need to be wasting everyone's time with such a petty incident.

The sleepy crowd was startled to life by Rob Kearney’s acrobatic leap into the night sky. And away he went, almost all the way, but for Garvey to catch him with 15 metres out.

Otherwise the second half was a dithery affair but Leinster, when it mattered, looked slick again. Especially Madigan with seven kicks at goal hardly punctuated by one aberration under the posts. He also finished at outhalf.

Alive and well then. Now, can they enact a similar pulverisation on Wasps next Saturday in Coventry? Such a victory would confirm the rise of Murphy, Jack Conan, Moore, his rival Tadhg Furlong (he of the fifth try), even Darragh Fanning (sixth try), Luke McGrath (seventh) and this new generation.

“It’s hugely important that we have the confidence in them,” said man-of-the-match Toner. “We know they don’t have a huge amount of experience, but to see lads come on and know they can do a job for you is massive.

“Two tries in two weeks for Tadhg Furlong? He’s a great young player and obviously you’d always back Luke for a score as well. They’re two guys for the future and then you have two other young guys like Jordi and Jack Conan. It’s really positive for the province, and there’s a huge amount of talent in the academy as well.”

They know defeat in Coventry will start the grumbling again. All along the fine line that is January rugby.

“I think we’re getting there,” Toner added. “We had the confidence building and we knew we had it in us. We know the talent we have in the squad.

“Not getting those performances until now has been frustrating, but now in the last couple of weeks the performances have been pretty positive.”