Leinster (20) 34
Tries: Jennings, Nacewa, McFadden, Madigan. Cons: Nacewa 4. Pens: Nacewa 2.
Blues (6) 23
Tries: B Davies, Rees. Cons: Parks 2. Pens: Parks 3.
Blues' Dafydd Hewitt collides with rival Leinster centre Brian O'Driscoll
Leinster had to dig deep to hold off Cardiff Blues at the RDS Showground.
The Welsh visitors had fought back from 20-6 down at half-time to take the lead thanks to Dan Parks' boot and tries from Bradley Davies and Richie Rees.
But Leinster replacement Cian Healy sent centre Fergus McFadden crashing through to retake the lead, with Ian Madigan's try making sure of victory.
The fly-half's score secured a bonus point for Leinster, while also denying Blues a consolation losing bonus point.
Jonathan Sexton missed out on his first appearance of the season for Leinster when injuring himself in the warm-up, so academy player Madigan stepped in at number 10 for only his second start for the province.
Blues travelled on the back of an encouraging bonus-point victory over Edinburgh last weekend, and gave competitive debuts to prop Tom Davies and New Zealand flanker Michael Paterson.
The game was only four minutes old when Isaac Boss managed to spring through a gap between Deiniol Jones and Bradley Davies, and feed the supporting Jennings for the opening try which man-of-the-match Nacewa converted.
Blues encountered scrum problems through the first half, so much so that newcomer Tom Davies had to be replaced on the stroke of half-time.
They fell further behind when slick hands from Richardt Strauss and Luke Fitzgerald gave Nacewa enough space to skip by Chris Czekaj for a try he converted himself.
Blue fly-half Parks knocked over two successive penalties to close the gap, with Casey Laulala beginning to cause problems for the Leinster defence.
But the hosts tightened their grip on proceedings, moving 20-6 clear at the break courtesy of a penalty brace from Nacewa.
The same player put in a try-saving tackle on Richard Mustoe as Blues began the second half with intent.
Scrum-half Rees had sparked a superb counter-attack out of the 22 and the vistors' new-found adventure was soon rewarded.
Parks punted a penalty to touch and lock Davies muscled his way over off the next phase, the fly-half adding the extras.
Then, after Leinster failed to convert a couple of promising attacking situations, the Blues squared the game at 20-20 thanks to a terrific team try.
Laulala's long pass set up an overlap on the right and a couple of well-timed deliveries from Davies and Mustoe sent Xavier Rush charging into the 22.
The Cardiff skipper's brilliant offload out of the tackle then put Rees in behind the posts and Parks comfortably converted.
The Scotland international tagged on a penalty for good measure and suddenly Leinster were behind, but the Irish were up for the challenge and they bounced back to deservedly take the spoils.
Replacement prop Healy drew two defenders on a barge through the middle to tee up McFadden for a sprint in under the posts.
Nacewa converted and in the final minute took his personal tally to 19 points as he topped off Madigan's fine snipe from outside the 22.
Leinster: L Fitzgerald; S Horgan, B O'Driscoll, F McFadden, I Nacewa; I Madigan, I Boss; H van der Merwe, R Strauss, M Ross, N Hines, E O'Donoghue, S O'Brien, S Jennings (capt), J Heaslip.
Replacements: J Fogarty for Strauss (55), C Healy Van der Merwe (61), S Shawe for Ross (67), M Galarza for O'Donoghue (78), D Ryan for Jennings (61), E Reddan for Boss (53), E O'Malley, for O'Driscoll (61), D Kearney for Horgan (49).
Blues: C Czekaj; R Mustoe, C Laulala, D Hewitt, T James; D Parks, R Rees; T Davies, R Thomas, S Andrews, B Davies, D Jones, M Paterson, S Warburton, X Rush (capt).
Replacements: R Williams, J Yapp for Andrews (49), T Filise T. Davies (41), J Down for Jones (58), B White for Warburton (71), M Williams, C Sweeney, G Evans for Laulala (72).
Referee: Andy Macpherson (SRU).