Guardiola's arrival as City head coach was marked by an outdoor fan festival at the club's training complex at the start of July and impromptu interviews with supporters, young and old, in the back of a black cab.
This was fun, likeable and charming Pep, decked out in his favourite smart-casual threads.
As commentators and fans exchanged his first and surnames with an easy familiarity, Pep stormed to five wins from five competitive games, City playing with dashing attacking verve and inverted full-backs and Aleksandar Kolarov sometimes deployed at centre-back.
His ruthless decisions over the respective involvement of Joe Hart and Yaya Toure in his plans at the Etihad Stadium also demonstrated an unswerving ruthless streak.
Such characters do not go through life without making enemies and dividing opinion and, perhaps fittingly, the Premier League's Guardiola love-in hit the buffers ahead of the Catalan renewing hostilities with a man who became his most bitter adversary.
There was mutual respect from Mourinho and Guardiola at their pre-match news conference - Sergio Aguero's retrospective ban for violent conduct meant the Portuguese could shelve his talk of officiating conspiracies for now, while his Catalan contemporary had no need to lambast "the f****** chief, the f****** boss" on the other side of town as he famously did in their Clasico days.
But that shared history on opposite sides of the Barcelona and Real Madrid divide brings added heft to this famous old fixture.
Peter Schmeichel told Omnisport that the Manchester derby was always one of the first fixtures he looked for during his decorated playing days at Old Trafford, even if the clubs were largely concerned with opposite ends of the top flight in the 1990s, if not separate divisions entirely.
The ex-Denmark goalkeeper praised Guardiola as a "fantastic" coach, but one who was "lucky" at Barcelona before making Bayern Munich "boring". With admirers like those, who needs enemies?
Guardiola told the assembled media on Friday that he respects Zlatan Ibrahimovic - an almost comedic stance given the raft of barbs sent his way by United's latest terrace darling since their time together at Barcelona turned sour in 2010.
While Ibrahimovic's part in the pre-match brouhaha amounted to folding up and parcelling clothes for City goalkeeper Claudio Bravo, his outspoken agent Mino Raiola allowed us to tunnel through his client's previous vitriol by launching his own attack on Guardiola.
"Guardiola doesn't have the balls to sit down with me," he said. Here's hoping Mourinho has not instructed the man who furnished him with Ibrahimovic, Henrikh Mkhitaryan and Paul Pogba this year to bring along the wine.
Elsewhere, the Manchester derby became a previously unexplored front in Real Madrid realpolitik.
Former Blancos president Ramon Calderon crossed the deepest schism in Spanish football to praise Guardiola in an interview with Omnisport. He prefers him to Mourinho, an appointment made by his predecessor and successor Florentino Perez.
At Barcelona, Luis Enrique fielded a question on the match after discussing Lionel Messi and Neymar's availability to face Alaves in La Liga. Back in England, Chelsea's Antonio Conte and Arsenal's Arsene Wenger had their say.
The dynamic of the game within Manchester has not changed a great deal. Monday morning bragging rights for Reds and Blues working side by side exist unchecked, irrespective of whether Peter Swales or Sheikh Mansour is in control of the City purse strings.
There have been previous golden periods in the rivalry. Matt Busby's fabled side won the championship in 1956 before City lifted that year's FA Cup amid Bert Trautmann's neck-breaking exploits at Wembley.
Sergio Aguero's unforgettable 2012 deeds were not the first time City pipped United to the title on the final day of the season. That came in 1968, with Colin Bell, Francis Lee and Mike Summerbee in the blue corner facing down George Best, Dennis Law and Bobby Charlton in the red.
Wembley meetings and title showdowns have garnished recent years of the rivalry, but only now does it truly resonate in Barcelona, Madrid and beyond.
All this, with Guardiola and Mourinho saying very little at all. If sparks fly on Saturday, they will flicker around the globe. This game has always meant the world in Manchester; it now means more to the world than ever before.