It was all going so well for Jose Mourinho.
Three wins from three heading into Saturday's Manchester derby meant the Portuguese manager was confident his side would maintain their perfect start to the new season.
And yet, thanks to goals from Kevin De Bruyne and Kelechi Iheanacho, Manchester United slumped to a 2-1 defeat and fell three points behind their local rivals.
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By no means should the defeat worry Mourinho, but it was an early sign that perhaps there are cracks in his expensive squad.
What the former Chelsea manager must ultimately learn from are the four mistakes he made against Pep Guardiola and Manchester City.
Henrikh Mkhitaryan was yet to complete 90 minutes for United ahead of Saturday's clash yet Mourinho, inexplicably, decided to start the Armenian.
What makes the Portuguese's decision even worse is the fact Mkhitaryan was only confirmed as fit two days before.
Mourinho opted to drop Juan Mata in favour of his £26 million summer signing but, after watching him lose the ball on a number of occasions, was wrong to do so.
Mata has been in good form this season and deserved to start; Mkhitaryan lacks match fitness and should have been brought on in the second half, like his performance suggested.
BRINGING ON MARTIAL TOO LATE
Mourinho waited until the 81st minute to bring Anthony Martial on against City, at which point United were desperate for an equaliser and had been for the best part of 45 minutes.
The Frenchman's pace, energy and skill would have been ideal earlier on in the game, when he had a better chance of making a genuine impact.
It's been a frustrating start to the new season for Martial - he's yet to score in the Premier League - and featuring against City for longer than nine minutes would have undoubtedly helped his confidence.
Instead, he's now in limbo waiting for his manager to realise how wrong he is to keep leaving him out.
NOT STARTING RASHFORD
A winning goal against Hull City two weeks ago and a hat-trick for England Under-21s should have been more than enough for Marcus Rashford to start against City.
However, the 18-year-old was forced to wait until half-time to make an appearance when he should have started, even if on the right flank ahead of Mkhitaryan.
Confidence is key for young players and to bench someone who has been in such scintillating form recently is poor management from Mourinho.
The fact Rashford scored against City last season was another reason for him to start against a defence that lacked pace at Old Trafford.
BLAMING HIS PLAYERS AFTERWARDS
"Look, I have two or three players in the first half who if I know what was going to happen I would not play them. Sometimes players disappoint managers.
"They didn’t give me what I want. It’s their fault, it’s my fault."
That's what Mourinho said after his side's defeat and, whilst he shared the blame, it was wrong of him to blame the players he wrongly fielded.
One suspects he was unimpressed with Mkhitaryan and Jesse Lingard, who were hauled off at half-time, but neither of them should really have started in the first place and besides, it's unproductive to criticise your players after one defeat.