MILAN — New Juventus coach Massimiliano Allegri kicked off his time in charge with a victory as his team won 1-0 at Chievo Verona in the Serie A opener on Saturday.
Roma, last year's runner-up, won 2-0 at home to Fiorentina, with Radja Nainggolan and Gervinho scoring.
Juventus showed that little has changed from the spirit which drove it to three consecutive league titles as Martin Caceres helped open the scoring in the sixth minute.
Caceres headed Carlos Tevez's corner toward goal, although it eventually went in off the back of Cristiano Biraghi.
Juventus had several chances to extend its advantage and hit the woodwork three times in the first half.
"There are good signs, I'm happy enough," Allegri said. "But there is a lot to improve. I was more worried than angry at the end. We should have closed the match and instead we risked them equalizing."
Roma got off to a record Serie A start of 10 straight wins last season, before faltering as the campaign wore on. It once again looks set to push Juventus all the way.
"We're strong and we're not going to hide it," Roma midfielder Daniele De Rossi said. "This year for the first time I say that we can aim for the title. But aiming for it is different to making it seem very easy."
Allegri was hired by Juventus last month, replacing Antonio Conte, who resigned — and later became Italy coach.
For his first competitive match in charge Allegri was without the injured Andrea Pirlo, Alvaro Morata and Andrea Barzagli while Giorgio Chiellini was suspended.
Fernando Llorente and Sebastian Giovinco had been suffering from flu and were only fit for the bench, which meant that Kingsley Coman started and the 18-year-old impressed on his debut.
Juventus began brightly and Tevez, who had been left far too much space inside the penalty area, drilled narrowly wide of the left post inside the opening minute.
After taking an early lead it had several chances to double its advantage but Claudio Marchisio lifted Paul Pogba's deft pass over the bar.
Vidal, who had been the subject of intense transfer speculation in the offseason, had an effort cleared off the line before then heading the resulting corner off the right post.
"It was important for us to win today, we have a long season ahead and need to be ready to battle every weekend," Allegri said. "Now we have the international break to hopefully get at least one of so many absentees back."
Chievo was struggling and its best opportunity came in the 25th minute as Valter Birsa raced down the left flank before centering for Ezequiel Schelotto, whose effort flew well wide of the left post. Juventus hit the woodwork again shortly before halftime when Tevez fired Stephan Lichtsteiner's cross off the bar.
From the resulting corner, Caceres also hit the bar.
Coman almost capped a brilliant performance with a goal seconds after halftime, but his curled effort from just outside the penalty area scraped the outside of the right post.
Juventus was nearly made to rue its wasted opportunities when goalkeeper Gianluigi Buffon was forced into a fantastic save at point-blank range to deny Maxi Lopez.
In the capital, Roma was also struggling with injuries so Kostas Manolas — who only joined last week — was thrown straight into the back four along with fellow new signings Ashley Cole and Davide Astori.
The attacking pace of Gervinho and Juan Manuel Iturbe caused Fiorentina no end of problems.
Roma took the lead in a move started and finished by Nainggolan. He threaded the ball through to Gervinho and was on hand to smash the rebound into the bottom right corner after his teammate's effort had been parried by Fiorentina goalkeeper Norberto Neto.
Fiorentina coach Vincenzo Montella responded by immediately taking off Australia international Joshua Brillante, who had given the ball away in the buildup.
Gervinho should have extended Roma's lead early in the second half following a swift counterattack but, after a fantastic run, the Ivory Coast striker saw his shot smothered when he might have done better to square it to unmarked teammate Miralem Pjanic.
Moments later Gervinho also had an effort blocked by Neto.
Roma goalkeeper Morgan De Sanctis had had little to do all match but kept his team in the lead shortly after the hour mark when he tipped Josip Ilicic's free kick onto the crossbar before pulling off another great save to deny Khouma Babacar.
Gervinho sealed the result in stoppage time, beating the offside trap to race onto Nainggolan's through ball, before rounding Neto and firing across into the back of the net.