Ronaldo stole the show with two headers and a late penalty kick on an ecstatic night for the Turin side.
With Atletico Madrid packing their defence, Ronaldo made the crucial breakthrough in the 27th minute when he rose to head in Federico Bernardeschi’s cross at the far post.
The 34-year-old levelled the aggregate scores in the last-16 clash three minutes after halftime with another towering header, this time from Joao Cancelo’s cross.
With four minutes left, Bernardeschi powered into the Atletico area, and was pushed in the back by Angel Correa.
Ronaldo then blasted home the resulting penalty kick for his hat-trick, his team’s victory for a 3-2 aggregate win and passage into the quarter-finals.