Ronaldo: Supercoppa triumph just the start for Juve
The prolific forward made the breakthrough just after the hour in Jeddah, with Milan's task made even more difficult by a late sending off for Franck Kessie.
It marks the first medal Ronaldo has won as a Juve player since he joined from Real Madrid in a €112million deal in the close season and the Portugal star hopes this is the beginning of bigger and better things.
Speaking to Rai Sport, he said: "It was a very difficult match, it's very warm and hard to play in these conditions.
"We played well, created a lot of chances and obviously I am happy to have scored the winning goal.
"It was my intention to start 2019 with a trophy, I have my first title with Juve and I am very happy.
"But it is only the start, we will take it one step at a time. We've got this trophy, now we must keep working hard to achieve the next one."
THE #SUPERCUP IS OURS FOR THE 8TH TIME!!!!!!!! #SuperJuve #JuveMilan #ForzaJuve pic.twitter.com/foFy1ieIQV
— JuventusFC (@juventusfcen) January 16, 2019
Even though Serie A is only at its halfway stage it seems inevitable that Ronaldo will add Italy's top-flight title to his medal haul with Juve unbeaten and nine points clear of second-place Napoli.
But Ronaldo is refusing to rest on his laurels in his bid to win major honours with Juve.
"Serie A is always Juve's main objective," he added.
"We are top of the table, but it's a very long tournament and it's going to be tough, so we need to keep working."