Rhys Carre claimed a quickfire try double as Josh Turnbull made his 200th appearance for Cardiff Rugby, but it was Leinster who came out on top at the Arms Park.
Prop Carre stormed over twice in the space of four minutes just before half-time to give the hosts a 15-12 lead at the interval.
At that point, it looked as though they might just repeat their memorable 29-27 victory from when the two sides last met at the ground back in January 2022 when Jarrod Evans landed the last minute match-winning penalty.
But it wasn’t to be as Leinster turned to the carrying power of their forwards after the break, with replacement prop Michael Milne crossing twice as they secured a bonus point victory to move back to the top of the URC.
There was a late consolation try for home winger Aled Summerhill, while Thomas Young put in another big display on the openside flank.
It was a very special night for that great servant of Welsh rugby Turnbull who was bringing up his double century for Cardiff
Back to captain the side from the second row, he walked out ahead of his team-mates - accompanied by his wife and two daughters - to receive a big ovation from the 7,730 crowd.
When the game got underway, it was Leinster that came flying out of the blocks as they went 12-0 up inside eight minutes.
Their first try came after Tinus de Beer’s attempted chip over the top was charged down by second row Jason Jenkins, with the ball ricocheting into the hands of prop Thomas Clarkson who burst forward and handed a run-in to wing Rob Russell.
Fly-half Ross Byrne converted ahead of Cardiff being forced into a very early change with No 8 Lopeti Timani coming off with a hamstring problem to be replaced by Alun Lawrence.
The visitors then extended their lead as they employed one of their numerous close-range tap penalty moves.
This time it was flanker Scott Penny who made the carry up to the line and No 8 Max Deegan who provided the finish, spinning over.
At this point, the signs looked ominous but Cardiff responded by opening their account through the boot of De Beer after flanker Will Connors was pinged for not releasing in a tackle.
The South African fly-half soon had the chance to double the hosts’ tally but his penalty rebounded off an upright.
For the next 20 minutes, it was back and fore with both sides having their spells.
Leinster’s offloading game and ability to break the line was a real threat, but brave scramble defence just about managed to keep them out.
As for Cardiff, they were looking to play with width and release their wingers Summerhuil and Owen Lane, either through moving the ball down the line or via pinpoint cross kicks from De Beer.
The hosts had to make another switch on 24 minutes when No 15 Jacob Beetham took a blow to the face and came off for a HIA which he failed. His exit saw Ben Thomas move to full-back and Willis Halaholo come on in the centre.
While it was developing into an intriguing battle of thrust and counter thrust, it seemed as though we might get to the break with no further scores - but Rhys Carre had other ideas.
His first try came from a lineout move straight off the training field, with Liam Belcher throwing to Shane Lewis-Hughes at the tail and the ball being popped down to Ellis Bevan who fed the onrushing Carre.
There was no stopping the loosehead who bumped off one defender and took another with him as he stormed over the line, enabling De Beer to add the conversion.
Cardiff now had the wind in their sails and moved the ball wide for openside Young to burst away down the right touchline.
After cutting inside, he was brought down just short of the whitewash but an offence at the breakdown saw full-back Jordan Larmour yellow carded.
Cardiff opted for a tap penalty and it paid off with that man Carre picking up from a ruck and driving through lock Ross Molony to spin over the line.
It was some double whammy from the powerful prop and it gave Cardiff a three point lead at the interval.
But despite being down to 14 players, Leinster hit back after the break - eventually.
Tighthead Clarkson was initially adjuged to have touched down but following a TMO check the score was ruled out with replays showing he had been held up by Young.
The visitors were not to be denied for long however.
Sticking to a pick-and-go approach, they ultimately got their reward when replacement loosehead Milne burrowed over.
They went further ahead on the hour mark when Milne drove over for his second with the help of a couple of his pals to secure the four try bonus point.
Close quarter carrying was once again the order of the day for their fifth touchdown, with replacement hooker John McKee the front rower to profit this time.
But it was Cardiff who had the last word as winger Summerhill was worked over in the left corner with Ellis Jenkins giving the scoring pass.