His worst game as a United player by a country mile.
It wasn't supposed to be this way. After a brilliant start to his Manchester United career, fans began to dream that Romelu Lukaku was going to be the man to fire Jose Mourinho's side to the Premier League title.
However, the goals have dried up for the Belgian and Sunday's Manchester derby represented the morale-crushing nadir of his brief time at Old Trafford. By the end of a harrowing 90 minutes, it was little surprise to see him pull his shirt up over his face. I wouldn't want to look at anyone after that kind of performance either.
But there was nowhere to hide for the 24-year-old and it has only armed his naysayers with further ammunition.
Lukaku was at fault for both of City's goals. For David Silva's opener, the forward switched off and allowed Nicolas Otamendi to get to the ball ahead of him, while his hacked attempt at a clearance paved the way for Otamendi to clinch the game for City.
Lukaku's status as a United player will not be determined by his defensive contributions, but his lack of decisiveness in the area of the pitch in which he supposedly specialises was particularly telling.
There was one moment when Jesse Lingard played a pass through to the Belgian. Faced with Eliaquim Mangala, the striker never looked settled on the ball before spraying a shot high, wide and not-so-handsome.
Then, with six minutes remaining, he passed up the best chance to score, blasting a close-range effort straight at Ederson after a pinpoint first-time cross from Anthony Martial.
https://twitter.com/FutbolBallack/status/939927224597217280
Considering United were outclassed and well beaten in midfield, it's somewhat surprising that the home side were able to find Lukaku. But for such an accomplished finisher, Lukaku's inability to shape the outcome of this game was striking.
The former Everton man has long struggled to distance himself from the popular perception of him as a flat-track bully.
His displays since joining United haven't helped. In five games against the other members of the top six, Lukaku has failed to find the net. However, while he certainly contributed in last week's win over Arsenal, here he was simply dreadful.
He completed 38% of his passes.
38%.
https://twitter.com/SportsJOEdotie/status/939926108316884992
He also lost eight aerial duels and was dispossessed twice. His touch deserted him and he didn't look to be on the same wavelength as Anthony Martial, Marcus Rashford (who found the net with his only chance) or Jesse Lingard.
It leaves Mourinho with a big decision to make. Lukaku still carries as much goalscoring threat as anyone in this United side but his performances have not been acceptable for a €90 million striker.
With Zlatan Ibrahimovic fit again, and with Martial or Rashford capable of operating up front, it will be interesting to see if Mourinho drops Lukaku to the bench for Wednesday night's clash with Bournemouth.
In a game you would expect United to dominate, Mourinho may view it as the ideal opportunity to give Ibrahimovic his first start since regaining full fitness.
The United manager has not been afraid to drop United's struggling stars. Just ask Henrikh Mkhitaryan. But it's not a stretch to suggest that Lukaku's dip in form has been every bit as alarming as the Armenian's.
If there was any consolation for Lukaku to take away from this chastening initiation into the Manchester derby, it's that it can't possibly go any worse in future games.
