David Moyes will just want to dig up a large hole and hide himself in it - he might also want to take a few of his Manchester United players with him as well.
In a day that all United fans will want to forget quickly, Manchester City turned on the style, and how, to batter their neighbours 4-1 in their English Premier League game at the Etihad.
Sergio Aguero got things started off in the first half, before Yaya Toure slotted in the second right on the stroke of halftime. Aguero grabbed a brace early in the second half with Samir Nasri making it a stunning 4-0.
Wayne Rooney grabbed a consolation goal late on, but it was completely and entirely City's day.
Moyes was dealt a major blow prior to the start of the Manchester Derby, with talisman Robin Van Persie ruled out after picking up a knock in training on Saturday.
Danny Welbeck came in for the Dutchman, with Ashley Young replacing Shinji Kagawa on the right as the Japanese dropped down to his now familiar place on the bench.
Manchester City, whose team did not have too many surprises, had the first chance, with Nemanja Vidic gifting the ball to Jesus Navas, who could not keep his shot down.
Howard Webb laid out the law with an early yellow card, shown to City defender Matija Nastasic, for clattering into the back of Chris Smalling.
It was all City really in the first 15 minutes, with United struggling to get a foothold in the game and unable to even string a few passes together.
City were rewarded for their endeavour in the 16th minute and what a cracking goal it was.
Samir Nasri, in for the injured David Silva, drove down the left before waiting for Aleksandar Kolarov to make a down on the outside. The former Arsenal midfielder then played Kolarov in with an audacious flick, before the left-back swung in a vicious cross.
The ball was just behind Sergio Aguero at the far post, but the City forward swung his left foot perfectly at it to smash it into the back of the net.
After the goal, it was still City that controlled the proceedings with United taking their time to find their feet - Wayne Rooney was given a yellow card inside 30 minutes for persistent fouling as frustration got the better of the Englishman.
Slowly the away side grew into the game, but just when it looked like they would go into the break only a manageable goal down, City struck the hammer blow with the second in first half stoppage time.
It was just poor defending from United as Alvaro Negredo rose above everyone to head the ball towards goal, with Yaya Toure reacting quickest to guide it into the back of the net from point-blank range.
Man City and their supporters were in dreamland - a place where everything is perfect and the blue half of Manchester is always top dog - after five minutes of the second half.
It was 3-0 just two minutes in, courtesy another sweeping move from Pellegrini's men. Kolarov fed Negredo, who showed great strength to hold off the United defender on the byeline before chipping a perfect cross for Aguero to finish.
On 50 minutes the score read an almost unbelievable 4-0 with Jesus Navas marauding down the right unchecked before finding Nasri at the far post to volley home.
United were done and dusted now and their evening was pretty much summed up on 55 minutes when Rooney missed a really presentable chance, firing high over the crossbar from ten yards out.
Rooney, though, did have the final say, albeit a rather hollow one, when he curled a peach of a freekick into the top corner.
What a result it is for City, though, and could be just the kickstart they need to push on, while Moyes and this United team's character in coming back from this big loss will be seriously tested over the next few weeks, starting with the Capital One Cup tie against Liverpool in midweek.
