Romelu Lukaku missed out through suspension, but Inter welcomed back Marcelo Brozovic, Arturo Vidal and Alexis Sanchez amongst others with Ronaldo up top for the visitors.
Inter had the breakthrough nine minutes gone after Lautaro Martinez beat Matthijs De Ligt to a cross from Nicolo Barella for a neat finish beyond Juventus goalkeeper Gianluigi Buffon.
It was short-lived though as Ronaldo put the Old Lady level from the penalty spot midway through the first half from a foul in the area by Ashley Young on Juan Cuadrado.
Ronaldo helped himself to a brace with ten minutes to the break after he pounced on miscommunication in the Inter defence to race clear for a smart finish from a tight angle.
The Nerazzurri targeted a comeback soon after halftime when a long-rang strike from Young following a loose ball from a free-kick forced Buffon to palm for a corner-kick.
However, a promising move down the right by Cuadrado 55 minutes in nearly handed Juve a third but Bernardeschi was unable to finish off the Colombian's supply.
Inter refused to give up and threatened the equaliser two minutes later through a smart attempt from a counter-attack by Sanchez, but Merih Demiral produced a goal-line clearance.
With the closing quarter looming, Inter decided to bring on Danish international Christian Eriksen in the place of Vidal.
Juventus struggled to get on the front-foot late on, as the hosts went close again with an acrobatic effort from Barella however the Bianconeri still came victorious ahead of next Tuesday's return-leg.
