But Leinster, and Fergus McFadden's 15-point haul, ensured there would be no repeat as they held of a comeback effort in the second half with Heineken Cup hero Eoin O'Malley scoring an important try midway through the second half.
Treviso will look back with regret after Tobias Botes lost his range during the second half missing three second-half kicks.
Leinster No.8 Leo Auva'a got the ball rolling early on as he crossed for the first try after just a minute, McFadden adding the conversion.
Botes pulled Treviso back with a penalty but Leinster looked to be running away with it when former Connacht flier Fionn Carr raced in for a second try after just eight minutes, McFadden making it 14-3 with the conversion.
But Treviso showed great spirit to come back into it through two more penalties from Botes on 12 and 21 minutes.
Three minutes later McFadden extended the lead with another penalty of his own, but Treviso finished the half the stronger with Botes adding another penalty to make it 17-12 at the break.
Botes added another penalty immediately five minutes into the second half to put Treviso back within two points, only for McFadden to match him three minutes later.
However Italian international replacement Manoa Vosawai crossed after 50 minutes but Botes missed the chance to put his side in front with the conversion.
And McFadden made him pay with another penalty to put Leinster back in front before Botes again missed a penalty chance.
Ian Madigan, starting instead of the rested Jonathan Sexton, took over the kicking duties for Leinster but he missed his first shot at goal.
But it made no difference as O'Malley, the hero against Glasgow a week ago, again got himself on the scoresheet, McFadden adding the extras to make it 30-20.
And despite Shane Jennings' late sin binning, the reigning European champions were able to hold on and overtake the Ospreys at the top of the RaboDirect PRO12 ahead of the Welsh region's trip to Connacht.
There was still time for Botes to miss a late penalty as Treviso missed out on even a losing bonus point.
|Benetton Treviso Score Card|
|Leinster Rugby Score Card|