The Portuguese started against his old rivals Atletico Madrid, with the Bianconeri winning the game 1-0 thanks to a sensational free-kick from Paulo Dybala.
But from the outset, Ronaldo - as he always seems to do - attracted all the attention due to the fact that he was sporting a headband.
Now, headbands are pretty commonplace in sport, but only because there are many athletes across that world that have long hair.
Ronaldo? Absolutely not, as the Portuguese's hair is so short that it has zero chance of interfering with his vision.
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Take a look for yourself below.
It just looks weird, right?
Ronaldo's new-look was a heavily discussed topic on Twitter and here are some of our favourite reactions.
We cannot unsee the 'dinner lady' comparison. Sorry, Cristiano.
There was also always going to be a number of tweets reminding the Portuguese and his legion of fans about his eternal enemy Lionel Messi sporting a headband earlier in his career.
It was a frustrating night for Ronaldo against Atletico, with the 34-year-old appearing to still be feeling the effects of his niggling knee injury.
He was unable to link up with Dybala and Aaron Ramsey, but Maurizio Sarri opted to keep the Portuguese on the pitch for 90 minutes.
Against Lokomotiv Moscow and AC Milan before the international break, Ronaldo was hauled off by the Juve manager, leading to rumours of a breakdown in his relationship with Sarri.
But if Juve are to end their Champions League drought this season, they will need their star man fit, firing and happy.
They may also have to adjust to his bold new look...News Now - Sport News