Roy Keane was left 'shocked' after Man City blasted four goals past Man United in the first half of their derby 6-3 derby win at the Ethiad Stadium.
It is the second time this season that the Red Devils have trailed 4-0 at the break - with the other coming against Brentford - but today's performance will seriously disappoint manager Erik ten Hag, who looked to have turned a corner after some early struggles.
Man United were better after the break - with goals coming from Antony and an Anthony Martial brace - but the home side scored two themselves to run out easy winners.
Phil Foden swept the ball into the net in the opening minutes after Man United switched off in the box, before Erling Haaland's header was adjudged to have cross the line for a second.
The Norwegian striker made it 3-0 after getting on the end of a sublime Kevin de Bruyne cross before Phil Foden hit a fourth just before the break after Haaland turned provider.
Speaking on Sky Sports at half time, Roy Keane gave a typically blunt assessment of Man United's display.
"I almost can't believe what I'm watching," Keane said.
"There's maybe a lack of belief. We gave them some plaudits before the match, and there were some question marks around players Man City were missing but it has been easy for them.
"Man United have been poor defensively, their passing has been sloppy, the two lads in midfield - McTominay and Eriksen - are getting pulled everywhere.
"It could get a lot worse. What do you say if you are the manager at half time?
"I can't believe how bad Man United have been."
Antony hit a cracker into the corner of the net to reduce the gap before Haaland completed his hat-trick after being picked out by Foden, who also netted his third after the Norwegian star returned the favour.
Anthony Martial headed another goal back before a late penalty put some respectability on the scoreline on what was a tough day for the red half of Manchester and a joyous one for the blue side.