Cristiano Ronaldo’s first-half hat-trick helped Juventus to a 3-1 win over relegation-threatened Cagliari.

Cagliari made the brighter start and were fearless in sending men forward as they looked to shock a Juventus side injured from their midweek Champions League exit.

But the Old Lady and Cristiano Ronaldo dealt the sucker-punch against the run of play after just 10 minutes, with the Portuguese leaping highest for a Juan Cuadrado corner to send a trademark bullet header past Alessio Cragno.

And 15 minutes later Cragno was helpless again as he brought down the onrushing Ronaldo inside the box, handing Juventus a penalty that the Portuguese hammered down the middle after picking himself up.

A hat-trick looked inevitable, and the number seven had his third with just over half an hour played. Federico Chiesa found him on the right flank, and after cutting inside on his left, Ronaldo found the top corner with an unstoppable effort.

Cagliari appeared unphased by their three-goal deficit and continued to hassle and harry a nervous Juventus backline.

Duncan was the first to sting Wojciech Szczesny’s palms with a vicious free-kick and moments later Nahitan Nandez did the same with a dipping long-distance effort.

And the hosts finally had the goal they deserved when Gabriele Zappa picked out the unmarked Giovanni Simeone inside the box with the striker sending a rifled, acrobatic effort into the net to pull a goal back.

Cagliari continued to press with Juventus forced to replace striker Alvaro Morata with defender Leonardo Bonucci.

But despite a spirited effort, Ronaldo’s first-half masterclass was enough for Andrea Pirlo’s men who go ten points behind Serie A leaders Inter Milan with a game in hand still to play.