Cristiano Ronaldo scored a second-half hat-trick to lead Serie A champions Juventus to a 4-0 win at home to Cagliari on Monday, as Zalatan Ibrahimovic made his much-anticipated return to action for AC Milan.
The Swedish striker, though, could not inspire his new teammates to victory after coming on as a second-half substitute in the goalless draw against Sampdoria.
Portugal forward Ronaldo struck for the fifth consecutive league game to move the champions back above Inter Milan in their first match since the Italian Super Cup defeat to Lazio in Saudi Arabia last month.
He pounced on a mistake in the Cagliari defence to break the deadlock four minutes after half-time, before adding the second from a penalty as he scored for the fifth league game in the row.
After setting up Gonzalo Higuain for the third in the 81st minute, he completed the rout by finishing off a counter-attack one minute later.
The win left Juventus top of Serie A with 45 points from 18 games, at least until after the later match when Inter Milan, who are three points behind, were taking on Napoli.
Ronaldo, who completed the 36th league hat-trick of his career, two more than Lionel Messi, took his tally this season to 15 goals, including 13 in Serie A.
"I'm happy with this first hat-trick. But the important thing is the team, which played very well," said Ronaldo. "We had to win to go ahead and put Inter under pressure."
Sixth-placed Cagliari defended stubbornly in the first half, restricting Juventus to one real chance when defender Merih Demiral's header thumped against the crossbar from a corner.
But it began to unravel for the Sardinians when Ragnar Klavan's pass across the face of the Cagliari area was intercepted by Ronaldo who glided past goalkeeper Robin Olsen and scored into the empty net.
Giovanni Simeone headed against the crossbar for Cagliari but they were undone by more careless defending when Marko Rog tripped Paulo Dybala as he weaved his way into the area and Ronaldo sent Olsen the wrong way from the spot.
With nine minutes left, Ronaldo sent substitute Higuain free down the left and the Argentine cut inside before scoring with a deflected shot.
One minute later, Douglas Costa burst forward and slipped the ball to an unmarked Ronaldo who placed his shot between Olsen and the near post.
Cagliari then hit the woodwork for a second time as Joao Pedro struck the post.
Welcome back to San Siro, @Ibra_official 👏🏻
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At the San Siro, Ibrahimovic made his debut for Milan coming off the bench after 55 minutes against Sampdoria.
The 38-year-old came on for Poland striker Krzysztof Piatek to deafening applause from the 58,000 crowd in his first appearance after rejoining the club last week.
But there was little else to cheer for the hosts who extended their winless run to three games.
In his previous stint at the club, Ibrahimovic helped Milan win Serie A in 2010-11, their last major trophy. He left for Paris St Germain at the end of the following season.
Milan also drew their previous home game 0-0, against Sassuolo, and Monday's result left them a miserable 12th in the Serie A standings, below Hellas Verona on goal difference.
"The disastrous defeat in Bergamo [against Atalanta] has remained within us," said Milan manager Stefano Pioli. "It is a shame not to have won. Ibra's impact was absolutely positive.
"He immediately gave support, but the team is not yet used to his presence, we could look to him more. His physical prowess gives us some more solutions, but we lacked quality from everyone."
New Fiorentina manager Giuseppe Iachini had to settle for a 1-1 draw against Bologna in his first game after taking over from Vincenzo Montella.
The Tuscany side had lead for most of the game after Marco Benassi volleyed in on 27 minutes but Riccardo Orsolini grabbed a point for Bologna deep into injury time.
Atalanta closed to within a point of fourth-placed Roma, who lost 2-0 to Torino on Sunday, with a 5-0 rout of Parma, having also beaten Milan by the same scoreline before the winter break.
The side from Bergamo were already three goals up before the break thanks to Alejandro Gomez, Remo Freuler and Robin Gosens, with Josip Ilicic adding a double in a nine minute second-half spell.
