City claimed a first ever treble of Premier League, FA and League Cups, as well as the Community Shield to take the count of major trophies to 10 in the decade since the club's fortunes were transformed on and off the pitch by Sheikh Mansour, a member of the Abu Dhabi royal family, AFP reported.
Guardiola now has 27 trophies in total as a coach, six of them since arriving in England three years ago, to go with 14 in four years at Barcelona and seven in three seasons at Bayern Munich.
One remains missing from his haul at City, the same one that escaped him in Germany. Guardiola's work at City will not truly be done until he lands the Champions League, like he did twice for Barcelona.
However, Guardiola claimed his side's relentless consistency across all competitions this season made the unique achievement of the treble even harder than his Champions League wins.
The Catalan has set new standards for City and English football, but remains hungry for more improvements next season.
"We won the Premier League for one point, so we are not so far away (from the competition) to be relaxed," added Guardiola.
"Liverpool show us how tough will be the future. This is the standards, the level we are going to face."
The fact that City does not seem content not only spells danger for the competition, but arguably for the health of the English game at large.
What once was England's showpiece occasion at Wembley had the feeling of a run of the mill Premier League procession and exposed a chasm between the haves and have-nots that is only becoming greater.
Guardiola could afford the luxury of leaving Sergio Aguero on the bench for the full 90 minutes. Kevin de Bruyne only featured for the final 40 and still won man-of-the-match.
Gabriel Jesus started just eight league games all season, but still took his tally for the season to 21 goals with a double.
City's back-to-back Premier League titles in the past two seasons were achieved with the two greatest points tallies England has ever seen.
Liverpool finished runner-up this season with the third highest in history, while City's emphatic Cup success came on the day Bayern's title win in Germany ensured all five top European leagues were retained for the first time ever.
Watford, by contrast, remains without a major trophy in its history. Despite the defiance of their fans as the goals rained in after halftime, the Hornets were helpless given the disparity of resources.
"We did it for the organization, for Sheikh Mansour, Khaldoon (Al Mubarak) and all the people working here," said Guardiola, at the end of a week where City's success on the field has been overshadowed by more questions over the club's conduct off it.
"This club made a big step forward for the investment from Sheikh Mansour definitely. You can do that without top players? No way."
The potential for a year-long transfer ban and season's exclusion from the Champions League remain in the horizon if FIFA and UEFA investigations into City find wrongdoing.
Such sanctions seem the only way Citizens’ progress can be halted with Guardiola already planning new arrivals before he tries to win it all again, starting with the Community Shield against Liverpool in August.