- Dusan Vlahovic (10', 67')
- Federico Chiesa (26')
- Luis Alberto (64')
Victory moved Juve up to 10 points from four games, a point ahead of both Inter Milan and AC Milan who play each other later on Saturday.
Lazio, who finished runners-up last season, are 15th with just one win and three losses so far.
"I am happy with the performance, the victory and the attitude of this team. Everyone was very good. Today there was a positive atmosphere," Juve boss Massimiliano Allegri told DAZN.
"We knew about Lazio's quality. We were good in the beginning to be aggressive, then after that we went a bit lower and were united and compact. We conceded little and nothing in the first half. It wasn't easy."
Juve went ahead in the 10th minute when Manuel Locatelli found Vlahovic in the box with a cross and the Serbia international took the defence by surprise when he swept home with an exquisite first-time effort.
Vlahovic nearly made it 2-0 moments later with a close-range header but missed his effort while, at the other end, Daichi Kamada forced Wojciech Szczesny into a fine reflex save to deny the Japan international an equaliser from a fiercely-hit volley.
Lazio boss Maurizio Sarri, who guided Juve to their last Scudetto in 2019-20, nervously chewed on a cigarette filter while he patrolled the touchline as a dominant and fired-up Juve constantly found gaps in his team's defence.
But the visitors struggled to make inroads in the first half and Juve eventually doubled their lead when Federico Chiesa netted his third goal of the season by beating keeper Ivan Provedel with an angled shot at the near post.
Lazio halved the deficit in the second half when an error in possession from Juve allowed Luis Alberto to pounce. With space to shoot, the Spanish midfielder pulled the trigger and beat Szczesny with a curling effort from distance.
But any optimism of a potential comeback evaporated two minutes later as Vlahovic restored the two-goal cushion when he chested down a long ball, opened up space in front of two defenders with a touch and fired home from the edge of the box.
- Fabio Maresca