Ronaldo's brace in the match also pushed him to the top of Serie A's goal scoring chart with 14 goals.
The 33-year-old gave Juventus an early lead in the 2nd minute after collecting the ball on the edge of the left-hand side of the box before planting a low-curling shot past Audero in goal for Sampdoria.
ZoneBut as Juventus failed to convert series of chances that came their way in the first half through Ronaldo, Dybala andMatuidi, they soon found themselves on level terms as the referee awarded a penalty to Sampdoria after a consultation with VAR.
Up step Mr reliable, Quagliarella, who equalized for Sampdoria in the 33rd minute from the spot to go into the break on level terms.
At the resumption of the second half, Ronaldo hit the woodwork in the 59th minute with a brilliant effort but he wasn't going to be denied again as he gave Juventus the lead in the 66th minute scoring from the spot.
However, Juventus thought they were denied a win in their last game of 2018 right at the death as Saponara forced theball into the net for Sampdoria in the 92 minute.
But the referee ruled out the goal after consulting with VAR to the delight of fans at the Allianz Stadium.
The victory sees Juventus move up to 53 points, 12 clear off their rival Napoli and has also stretched their unbeaten run in the league to 19 games.