Cristiano Ronaldo failed to score on his Serie A debut but champions Juventus won 3-2 at Chievo as Carlo Ancelotti began life as Napoli coach with a come-from-behind 2-1 victory at Lazio in two bruising opening matches of the 2018-2019 league season on Saturday.

Ronaldo, 33, who joined the Turin giants from Real Madrid last month in a deal worth 100 million euros ($114.5 million), clenched his fists with delight as his team earned all three points despite his four missed chances.

Italian Federico Bernardeschi scored the winner in injury time minutes after Chievo goalkeeper Stefano Sorrentino was knocked out and later hospitalised after colliding with the Portuguese superstar.

"Everyone was waiting for the goal. It's a shame he couldn't score but Sorrentino denied him a couple of times. He was happy we got the win anyway," said Juventus coach Massimiliano Allegri.

"We're still getting to know Ronaldo. He linked up well with (Paulo) Dybala today and I was impressed by how easily he slotted into the team."

Brazilian left-back Alex Sandro added: "I feel at ease with him (Ronaldo), and he's an excellent player.

"We understand each other, and we make a perfect team together. We have to go on like this."

The champions were made to work after Germany international Sami Khedira opened the scoring after just three minutes at the Bentegodi Stadium for the seven-time defending champions.

Polish striker Mariusz Stepinski headed in a 37th-minute equaliser for Chievo with Emanuele Giaccherini slotting in a penalty after 56 minutes following a foul by new Juventus signing Joao Cancelo.

But Chievo's Mattia Bani turned into his own net after 75 minutes following pressure from returning Juventus defender Leonardo Bonucci to pull the champions level.

In a frantic finale substitute Bernardeschi scored the winner after Mario Mandzukic had a goal disallowed as a result of Sorrentino's knock with Ronaldo.

The Chievo goalie was stretchered off and his replacement Andrea Seculin immediately conceded the decisive goal.

The 39-year-old's wife posted a picture on Instagram with Sorrentino in hospital, wearing a neck brace, after suffering a suspected broken nose and concussion.

"We let our focus dip after the first goal, we thought we had the match in the bag," said Allegri.

"A game like that will only do us good because it makes us realise how tough it's going to be to win the league again."

Ancelotti, meanwhile, was also relieved to keep a clean sheet as he returned to his native Italy after a successful trophy-laden nine years at clubs including Chelsea and Real Madrid.

The 59-year-old took over from Maurizio Sarri in the Napoli hotseat promising to end the club's 28-year wait for a Serie A trophy.

But the southerners were pushed hard by Lazio with last year's Serie A top scorer Ciro Immobile opening for the hosts after 25 minutes at the Stadio Olimpico.

Polish striker Arkadiusz Milik equalised just before the break after having a goal disallowed with Lorenzo Insigne scoring the winner after 59 minutes.

"I have a lot of emotion for the return to Italy and even more emotion for how we started the game," said Ancelotti.

"Then we conducted it well despite the final suffering. Their goal woke us up and we deserved to win."

"It was particularly special for me, because the Stadio Olimpico was my home as a player at Roma. I won so many games on that pitch."

Both games were preceded by a minute's silence for the victims of the Genoa bridge disaster with players taking to the pitch wearing black armbands.

Courtesy: Agence France-Presse (AFP)