Knights’ victory, which seemed unlikely at the break when they trailed the unbeaten leaders 21-8, saw them finish the highest placed of the five runners-up and will now visit Jersey Reds in the quarter-finals at the end of March.
“It’s a tough place to go but we’ve done well over there in the past and beat them there on the opening day of the season,” said director of rugby Clive Griffiths.
Despite the scoreline, and the fact that Leinster fielded over half-a-dozen first teamers including two Irish internationals, Griffiths said he still felt Knights were in the game at half time.
“I thought we’d played well and two of their tries were self-inflicted wounds and the other came when the referee got in the way of Michael Heaney from a scrum,” he said. “We just needed to tidy things up in certain areas and we did that.
“To score 29 points in the second half was a tremendous achievement and hopefully we can build on that performance when we return to Championship rugby at Nottingham this weekend.”
The Welshman admits the performance is likely to give him some selection headaches.
“Some of the (regulars) are going to have to look over their shoulder because the lads who came in did the business,” he said. “Once again the players who came off the bench did a great job.”
The game saw the debut of Samoan international forward Josh Tyrell, who played for just over an hour.
“He produced some typical Samoan hits in defence and to say it was his first game for us I thought he was outstanding,” said Griffiths.