Going into stoppage-time away at Atalanta, the Red Devils were trailing 2-1 and facing the prospect of potential elimination against Villarreal in their next European outing.
But Ronaldo delivered the goods for United once again, the five-time Ballon d'Or scoring an astonishing volley to level the scores at 2-2.
That strike was the Portuguese's second of the game after he'd stylishly equalised towards the end of the first half.
In the aftermath of the eventful game, Ronaldo has deservedly been praised to the rafters.
However, the superstar forward would likely not have had the opportunity to perform more last-minute heroics were it not for Eric Bailly.
The Ivorian centre-back was brought back into the side to replace the injured Victor Lindelof and was one of United's best players on the night.
And in the first half, Bailly was responsible for a superhuman-like block that prevented Duvan Zapata from putting Atalanta 2-0 up.
Paul Pogba's horrendous error near the penalty area gifted what appeared to be a relatively easy goalscoring opportunity to the Colombian striker.
But as the ball was dropping onto Zapata's foot to be volleyed past David De Gea, Bailly somehow managed to get his body in the way to deflect the shot behind for a corner.
Take a look at the sublime defensive contribution here...
Video: Bailly's last-ditch block vs Atalanta
Well played, Eric.
Ronaldo's unquestionable brilliance has resulted in Bailly's block slipping under the radar a tad, so we felt it necessary to highlight the defender's actions that also saved United on the night.
The Ivorian's performance in Bergamo was far better than that of Harry Maguire, the Red Devils' captain enduring another torrid evening at the back, including a mistake for Atalanta's second goal.
Atalanta 2-2 Manchester United Reaction Show | Football Terrace
When Lindelof and Raphael Varane return from injury, there's certainly a case to be made that Maguire, not Bailly, should be the man to drop out of Ole Gunnar Solskjaer's back three.