Ralf Rangnick fielded a strong side for the game against the Championship outfit, with Ronaldo named in the starting lineup alongside the likes of Bruno Fernandes, Raphael Varane and Marcus Rashford.
The legendary Portuguese forward enjoyed an eventful first 20 minutes in the game.
Ronaldo, just one day shy from his 37th birthday, nearly scored an outrageous bicycle kick in the seventh minute.
He made good connection with Luke Shaw’s cross but his acrobatic effort was saved by Joe Lumley.
Ronaldo was given a golden opportunity to find the back of the net 13 minutes later.
Paul Pogba was felled inside the box and the referee awarded United a penalty.
Despite Fernandes being on the pitch, it was Ronaldo who took responsibility and he placed the ball down on the spot.
Ronaldo looked confident but he inexplicably dragged his effort from 12 yards wide. Watch his miss below…
That was Ronaldo’s 29th missed penalty in his career, per BeIN Sports reporter Matt Critchley. It may be the worst he’s ever taken.
It’s just proof that even one the greatest footballers ever makes mistakes from time to time.
Fortunately for him, his miss didn’t prove too costly as United took the lead shortly after.
Declan Rice to JOIN MAN UTD? | The Football Terrace
Jadon Sancho bought down the ball inside Middlesbrough’s box with a terrific touch and then fired a left-footed effort which found its way into the net.
Ronaldo went close again later on in the half but his close range effort was blocked by Lumley.
There were no more goals for the remainder of the half as United held on to well deserved 1-0 lead at the break. In truth they could – and should – have been even further ahead.