Cristiano Ronaldo, 33, unintentionally played a role in Mario Mandzukic's second goal of the night on 75 minutes after Miralem Pjanic put the host in front at Allianz Stadium
Cristiano Ronaldo is still waiting for his first competitive goal in Italy but the Portuguese superstar made a 2-0 winning home debut with Juventus as Carlo Ancelotti's Napoli came from two goals down to beat AC Milan 3-2 in the second round of Serie A action.
Ronaldo, 33, unintentionally played a role in Mario Mandzukic's second goal of the night on 75 minutes after Miralem Pjanic put the host in front at Allianz Stadium.
The five-time Ballon d'Or winner joined the Serie A champion from Real Madrid in a 100-m-euro deal.
Juve have now won their opening two games after last weekend's 3-2 success against Chievo in Verona.
Lazio - fifth last season - have had their worst start in over a decade following last weekend's 2-1 defeat at home against Napoli.
Since Ronaldo joined Juventus, the club has become worth more than €1bn.— B/R Football (@brfootball) August 25, 2018
And he hasn't even scored a goal yet 💰 pic.twitter.com/ABmXx4UBfM
Lazio had ended Juve's two-year unbeaten home Serie A run last year, but apart from a Luis Alberto shot after an hour they failed to threaten.
In the first home game for the seven-time defending champion, Paulo Dybala and Douglas Costa started on the bench, with Allegri opting for Federico Bernardeschi and Mandzukic to spearhead the frontline with Ronaldo.
World Cup winner Blaise Matuidi set up Ronaldo for the champion's first chance after 19 minutes but it was Germany international Sami Khedira who rattled the woodwork with Lazio goalkeeper Thomas Strakosha diving to clear a Bernardeschi angled drive.
But the host broke through on the half-hour when Mandzukic knocked down a cross for Pjanic to power a half-volley into the corner.
Ronaldo came close after 63 minutes but headed just wide after connecting with a Joao Cancelo cross and again threatened on 71 minutes but Strakosha tipped over.
.@Cristiano: Man of the Match vs Lazio - Rating 8.10, Assists 1, Shots(OT) 5(3), Key Passes 3, Times Fouled 3, Aerials Won 2, Dribbles 2, Pass Accuracy 90% @juventusfcAugust 25, 2018
Full player ratings -- https://t.co/T8bzsUJWpM pic.twitter.com/VcmZylz9bq
Cancelo then set up Ronaldo for what looked destined to be his first goal for his new club, but the Portuguese star failed to control the ball directly in front of goal with Mandzukic taking advantage to finish off.
In Saturday's second Serie A game, Ancelotti got his first home win as Napoli coach as the southerners fought back from two goals down to edge Milan.
Giacomo Bonaventura sensationally opened for Milan after 15 minutes in the San Paulo Stadium with a Davide Calabria half-volley giving the visitor a two-goal advantage four minutes after the break.
But last season's runners-up turned it around in a second half with Piotr Zielinski bagging a brace and Dries Mertens sealing victory.
Ancelotti spent most of his career at Milan with the 59-year-old winning three Serie A and four European titles as a player and coach with the northern giant.
Napoli vs Milan was terrific. Successive weeks now Ancelotti's side have come from behind to win.— Alex Richards (@AA_Richards) August 25, 2018
Juventus 2 (Pjanic 30, Mandzukic 75) Lazio 0
Napoli 3 (Zielinski 53, 67, Mertens 80) Milan 2 (Bonaventura 15, Calabria 49)
SPAL v Parma, Cagliari v Sassuolo, Fiorentina v Chievo, Frosinone v Bologna, Genoa v Empoli, Inter v Torino and Udinese v Sampdoria