This was the kind of lethargic performance that José Mourinho has in mind when he warns that Manchester United will continue to exist in the shadow of their formidable neighbours next season. They are 19 points behind City and although this forgettable draw ensured that Mourinho’s side will finish second, a club of United’s might can only wince at the distance between them and Pep Guardiola’s record-breaking champions. The gap is vast and it will be a …