The former Real Madrid manager can have little excuse for his slip of the tongue after Manchester City's 3-1 win over Sunderland in the Capital One cup.
During a post-match interview with BBC presenter Mark Clemmit, a clearly delighted Pellegrini was basking in his first silverware as Manchester City boss, but unfortunately forgot which side Manchester side he actually manages.
When asked: 'Manuel how do you feel right now? There is big pressure being Manchester City manager, you've been here three-quarters of a season - what's going through your head?'
He replied: 'Oh very happy, very happy, I love pressure. I love pressure so I have to manage such a big team as Manchester United.'
The comments are quite striking and already the Manchester United fans are milking the comments for all they can as Twitter goes into overdrive:
Loool at Pellegrini saying that he loves the pressure of managing Man United, he is losing it, will be in an old peoples home by next season— Kieran Stapleton (@kieranstapes) March 2, 2014
Pellegrini - "I love the pressure of managing such a big team as Manchester United" Plonker alert. Christ.— ProudRed (@ProudRed85) March 2, 2014
When Man City boss Manuel Pellegrini said there's only one team in Manchester...think he was being serious. He thinks he's managing United.— Khurrum (@KWAH_89) March 3, 2014
Manuel Pellegrini: "I love the pressure of managing such a big team as Manchester United."He knows there's only one team in Manchester #mufc— Liam Nicholls (@LiamNicholls9) March 2, 2014
Unfortunately for Manchester United fans, the gaffe was nothing more than a slip of the tongue (and mind) for the nation's amusement.
After both Manchester clubs appointed their current manager's at a similar time, it's certainly United fans that got the raw end of the deal. Moyes is already being hounded out by a section of supporters and with Pellegrini winning his first silverware as City boss with the promise of many more to come, you wouldn't be forgiven for admitting that Pellegrini would have possibly been the better choice for United.