The Ireland fly-half was on target four times from the penalty tee and converted tries from centre Henry Chavancy and flanker Wenceslas Lauret as Racing maintained their perfect start to the tournament.
Ludovico Nitoglia scored Treviso’s only try, with full-back Jayden Hayward converting the 62nd-minute score to add to a successful penalty midway through the first half.
The result puts Racing at the top of Pool 5 with two wins from two fixtures.
* Sale suffered a second successive defeat as French heavyweights Clermont Auvergne powered to an emphatic 35-3 victory at Stade Marcel Michelin.
An early try by Clermont’s former Bath full-back Nick Abendanon put the home side in charge, before wing Napolioni Nalaga claimed two second-half touchdowns and substitute Aurelien Rougerie also scored, while fly-half Camille Lopez’s 15-point haul kept his team firmly in Pool 1 contention.
Sale, though, have fallen off the quarter-final pace in a punishing group that also includes Saracens and Munster.
* Harlequins beat local rivals Wasps 23-16 at Adams Park to go joint top of Pool 2.
The win gives them eight points to join Leinster on that figure and the two meetings between these sides in December are likely to decide the destiny of the Pool.
Harlequins were far more creative in attack, with their points coming from a try by the lively Charlie Matthews and a penalty try award, with Nick Evans kicking three penalties and two conversions.