#3 Bayern Munich - 9 goals (8 games)
A third consecutive German side on the list, Bayern Munich are Ronaldo's favorite Bundesliga team, having scored a staggering nine goals from just eight games against them.
What's also interesting is that he's scored them in multiples - a brace on three occasions along with a hat-trick - making the Bavarians look like an ordinary side.
His best, though, came in their quarter-final clash of the 2016/17 season, when he scored five goals over two legs, a double at the Allianz Arena followed by a treble at the Bernabeu.
To an extent, the Bavarians can claim to have salvaged some pride by shutting him out in both semi-final legs the following year, although Los Blancos once again prevailed on aggregate.
#2 Ajax - 9 goals (7 games)
Our last memory of Ronaldo playing Ajax was in the 2018/19 season when the Dutch side knocked his Juventus out in the quarter-finals, but he's come up against them several times in the past.
Failing to fire in only his first game, the Portuguese ace scored consecutively in his next six appearances, including a hat-trick in Amsterdam in 2012, his first in the competition.
He'd never lost (or even drawn) to the Lancers until his meeting with them in the Bianconeri colors just over two years ago, as the Serie A giants failed to win in both legs despite Ronaldo scoring.
#1 Juventus - 10 goals (7 games)
Ironically, Ronaldo's best record in the Champions League has come against his former side, Juventus, with him scoring 10 goals in seven games, the most a player has managed versus a single opposition in the competition.
What's also interesting is that the Portuguese ace has scored in every single appearance against the Bianconeri, including in the 2017 finals where his brace secured a stunning 4-1 win.
But his best moment was undoubtedly the spectacular overhead kick during Real Madrid's clash with Juventus in the quarter-finals of the 2017/18 season, that elicited a standing ovation from the Bianconeri faithful.
According to Ronaldo himself, it was that moment which inspired him to move to Turin later that summer.
But having now left the club three years later, there's always a chance that he could come against them some time in the Champions League and extend his unbelievable record.