The first half ended in a drab affair but early into the second half the former Real Madrid talisman pounced on a mistake in the Cagliari defence to break the deadlock. He later added the second from the penalty spot following the illegal upending of Paulo Dybala in the penalty area.
He then set up Gonzalo Higuain who was brought in to replace Dybala, for the third goal in the 81st minute and completed the rout by finishing off a quick counter-attack one minute later.
Although, this win changes nothing at the top of the Italian Serie A table because Juventus still occupies the second slot with 45 points from 18 games, the same number of points as the league leaders Inter Milan, but Inter Milan has a better goalscoring ratio.
Inter Milan defeated Napoli in a 4-goal thriller to retain their top spot on the Serie A table.