Serie A: Ronaldo starts year with hat trick while Zlatan makes his AC Milan debut

Cristiano Ronaldo recorded his second Juventus hat trick in a 4-0 win over Cagliari. (Photo by MARCO BERTORELLO/AFP via Getty Images)

Cristiano Ronaldo and Juventus made quite the statement to start the new year.

Ronaldo recorded a hat trick and Juve shot above Inter Milan atop the Serie A table with a 4-0 win over Cagliari. Over at the San Siro, Zlatan Ibrahimovic came on as a substitute but couldn’t help AC Milan avoid a 0-0 draw against Sampdoria.

Ronaldo hat trick fires Juventus to win

It’s Ronaldo’s second hat trick with Juventus, after his epic Champions League round of 16 effort against Atletico Madrid last spring, and his 56th overall for club and country.

After a scoreless first half, Ronaldo pounced on a bad giveaway and beat Cagliari keeper Robin Olsen to open the scoring Monday (via ESPN):

Ronaldo also converted a penalty in the 67th minute, then finished his hat trick with a goal in the 82nd minute, shortly after Gonzalo Higuain scored Juve’s third.

Inter has pushed the eight-time reigning Italian champions this season and even sat first on goal difference as the calendar flipped. But Ronaldo and Juve appear to have every intent of warding off their latest challenger.

Zlatan Ibrahimovic debuts but AC Milan settles for draw

If Milan wants to rescue its season, games like Monday’s need to be won.

Instead, Milan settled a point against relegation battling Sampdoria at home. In the first game of his second spell at the club, Ibrahimovic looked understandably out of sync with his teammates, most notably right winger Suso.

Zlatan Ibrahimovic's debut with Milan wasn't the memorable moment many hoped it'd be. (REUTERS/Daniele Mascolo)

Ibrahimovic came on in the 55th minute to replace starting striker Krzysztof Piątek, who is running out of chances to impress manager Stefano Pioli this season.

The Milan derby is looming on Feb. 9 against Inter, but in the meantime the Rossoneri have league fixtures against Cagliari, Udinese, Brescia and Verona, all of whom are comfortably mid-table in quality.

Problem is, so is Milan at the moment. Ibrahimovic and Co. need to start collecting wins to change that.

More from Yahoo Sports: