Leo Cullen admitted his side were worn down by a pumped-up, uncompromising Munster as Leinster slumped to a St Stephen's Day derby defeat at Thomond Park.
Tries from Simon Zebo, Ronan O'Mahony, Tommy O'Donnell and man of the match CJ Stander had the bonus point wrapped up by the hour mark for the vibrant hosts as they pulled clear at the top of the Pro12 table.
Cullen said crucial errors cost his men dear, and praised a powerful Munster performance.
"I thought the guys fought really hard towards the end to get back into the game," he told RTÉ Sport.
"It was just disappointing. We never really got enough momentum in the game.
"But a lot of credit to Munster. I thought they managed the game really well, were very physical, confrontational, and they wore us down."
Ronan O'Mahony went over just before the break and Rassie Erasmus's men scorched out of the blocks on the turnaround to earn the festive bragging rights,
That period decided the contest, with Cullen left with much to pore over before the New Year's Eve RDS collision with Ulster.
"We weren't accurate enough on our own setpiece ball," he added.
"We gave Munster too much momentum, or certainly too much possession where they got momentum off the back of that so they're areas we need to get better at.
"We lost a little bit of confidence from that try just before half-time. Once they get that rumble on...
"For the most part we weren't good enough and that's why we didn't get anything from the game.
"They're coming thick and fast at this time of the year. We'll assess all the bodies. It's a very short week, obviously five days.
"Ulster have a big advantage, because they played before Christmas, but we'll see what fit bodies we have and try and pick a team that can take on Ulster."
Listen to live coverage of Leinster v Ulster (KO 3pm) and Connacht v Munster at the Sportsground (KO 5.30pm) exclusively on RTÉ Radio One’s Saturday Sport.
