Joey Carbery scored two tries in his first start for Leinster as they opened the Guinness PRO12 season with a lacklustre 20-8 win over Benetton Treviso.

The 20-year-old Academy fly-half thrilled the RDS crowd with two first-half touchdowns, before Marco Fuser's 37th-minute try kept resilient Treviso in the hunt at 15-5 down.

Leo Cullen's men never hit the heights of last May's 50-19 thrashing of the Italians, but replacement hooker James Tracy settled the issue with a well-taken effort from a maul seven minutes from the end.

The hosts had stormed out of the blocks, wave after wave of attack leading to man-of-the-match Carbery cutting through to score under the posts inside three minutes.

A wayward first penalty attempt from debutant Tommaso Allan, coupled with the injury-enforced loss of captain Alessandro Zanni, saw Treviso remain scoreless throughout a somewhat listless first quarter.

It took another moment of magic from Carbery to lift the excitement level. Treviso failed to convert set-piece pressure into points and following a superb rip by Josh van der Flier, Carbery broke clear from his own half and jinked away from the covering Jayden Hayward to cross in the left corner.

Fergus McFadden was unable to add to his earlier conversion and although he soon knocked over a penalty for 15-0, a smart break by Allan eventually led to lock Fuser stretching over to the left of the posts. However, Allan blotted his copybook again from the kicking tee.

An increasing amount of penalties conceded and general sloppiness from Leinster allowed Kieran Crowley's charges to draw closer through Allan's right boot in the 52nd minute.

Scoring chances were very hard to come by as a lunging Marco Lazzaroni thwarted a promising break from Rob Kearney, and Hayward got up above McFadden to claim Carbery's cross-field kick.

Warm applause greeted the introduction of former Leinster player Ian McKinley off the Treviso bench.

Leinster's replacements, including debutants Andrew Porter, Jamison Gibson Park and Rory O'Loughlin, had the final say, though, as a masterful maul from the edge of the 22 teed up Tracy's try.

The bonus point push came late on but O'Loughlin was bundled into touch.