Teammate Nico O'Reilly had clearly impressed of late and therefore a starting berth for the youngster wasn't really a surprise either.
In so doing, at 20 years and 16 days, he became the fourth youngest defender to start for Manchester City against Manchester United in the Premier League after Micah Richards (18y 168d), Richard Edghill (19y 45d) and Matija Nastasic (19y 256d).
Before the game, United will have known that they had the chance to do the double over City for the first time in 15 seasons, but the fact that they started the match with their 16th different centre-back partnership this season - the most of any team in the Premier League in 2024/25 - hinted at more defensive woes for Ruben Amorim.
Bruno Fernandes captained the hosts as usual, with only Vincent Kompany (13) and Steve Bruce (7) starting a Manchester derby more often as a captain in the Premier League (Bruno's six times saw him draw level with Roy Keane, Ryan Giggs, Harry Maguire, Richard Dunne and Sylvain Distin).
Earliest yellow card in a Manchester derby since 2006/07
As the whistle blew to begin proceedings, Man City appeared not to be expecting such a fast start and Ruben Dias received the earliest card (38 seconds) in a Premier League Manchester derby on record (since 2006/07).
After 25 minutes, and despite completing just 14 passes in the final third, United had already had seven touches in Man City's penalty area, albeit they'd not had a shot from inside the box at that point.
Indeed, the lack of goalmouth incidents arguably contributed to there being little in the way of atmosphere inside the Theatre of Dreams as the half-time whistle sounded.
What should be one of the most keenly contested games of the season for both sides was a damp squib for much of the first half, with neither side showing any real urgency or purpose save for both Alejandro Garnacho and Nico O'Reilly who both had four touches in the opposition box before the break.
There were just eight shots in the first half and only two Premier League Manchester derbies on record (since 2003/04) have had fewer in the opening 45 minutes (6 in Jan 2023, 4 in Oct 2015).
Another goalless first-half for the Red Devils also meant that only Leicester City (7), Southampton (11) and Crystal Palace (12) have scored fewer first half goals in the Premier League this season than United's 13, whilst Man City only won 28% of their first-half duels - the lowest of any team in the English top-flight this season.
No wonder both Pep Guardiola and Ruben Amorim cut dejected figures as they paced down the touchline towards the tunnel.
Things didn't really get too much better in the second period either, though Mason Mount's first Premier League appearance at Old Trafford since December 7th against Nottingham Forest will have buoyed both player and club.
Casemiro could at least leave the pitch with his head held high as the Brazilian became the first player to win more than 10 duels in a Premier League Manchester derby (11) since Aaron Wan-Bissaka and Joao Cancelo both won 12 in March 2020.
In truth, there was precious little to get excited about in what was supposed to be a 'Super Sunday' fixture.
Pep Guardiola's side dominated the ball with 58.5% possession and with 338 passes in the opposition half compared to United's 174, but without Erling Haaland as their focal point, City's attack was largely toothless.
Omar Marmoush's sensational 100% completion from his 14 passes certainly deserved better from his teammates, and the striker also had three of City's five shots on target (from nine in total).
That was a far better return than United's two on target from 13 shots, though ultimately, the visitors just couldn't do anything with their chances.
Bruno Fernandes is still the man for Man United
Bruno Fernandes was, once again, head and shoulders above his colleagues in many aspects.
For example, the seven times he won possession for his team was the joint most in the game alongside Garnacho and Bernardo Silva. Three successful dribbles was also the best out of every player on show.
A 93% pass completion stat was just shy of Victor Lindelof's 93.3% and behind Mason Mount's 100%, however, the England international played just seven passes, Lindelof 15, whereas Bruno made 43 of which 40 found their target.
For the most part, a number of players from both sides huffed and puffed but never really looked like causing too many problems and the 0-0 draw was just the third Manchester derby to finish goalless since the start of the 2016/17 season across all competitions.
City could be reasonably happy after keeping a clean sheet in successive Premier League games for the first time since May 2024, though on the flip side, the inability to find the net saw Pep Guardiola's men failing to score in consecutive away matches in the Premier League for the first time since December 2020.
Worryingly for the hosts, since Ruben Amorim’s first game in charge at Old Trafford, only Leicester City (12) have failed to score in more Premier League games than Man United (8).
