Reunited in England's northwest after two confrontational years on either side of the Barcelona-Real Madrid rivalry, where Mourinho ended Guardiola's three seasons of La Liga dominance, United clearly hoped the feisty Portuguese could again get under the Catalan's skin.
But now in their third seasons in charge, Guardiola and Mourinho's reigns have instead seen a chasm open up with the blue half of Manchester now the dominant side of the city.
Win the Manchester derby on Sunday and City will already be 12 points clear of United just 12 games into the new season, a gap that has gradually widened in each of the past three years.
The season before their arrival, only City's superior goal difference saw them pip United to fourth place in the Premier League and Champions League qualification.
Despite a difficult first season for Guardiola in English football, City finished that campaign nine points ahead of their City rivals.
Last season the gap jumped to a record 19 between first and second place as City romped to the title with 100 points.
"There is a quality of the work, of the organisation, I think that is untouchable," even Mourinho admitted on Friday.