Their fans, who had celebrated the comeback victory at the Etihad last week, booed Jose Mourinho's side off the field after they lost to a team who had not won since January.
They clinched the silverware 24 hours later thanks to West Brom forward Jay Rodriguez's 73rd minute header at Old Trafford although Guardiola may have missed the crucial moment after opting for a round of golf with his son instead. "Probably because I won eight championships, I was not in the moon with the victory against them because that doesn't make me feel super happy".
Paul Pogba, the two goal hero last week, was substituted in the 58th minute after a poor display in which he also picked up a yellow card. The Gunners did draw 12 games that season, and won nothing else, but in avoiding a single defeat they completed a remarkable campaign that deserves recognition alongside the very best. "If I was in their position I would be very upset if someone said they won because United lost against West Brom".
After a mixed first season in England, Guardiola faced questions about whether his methods were a good fit for the Premier League.
"The last title was not 20 years ago it was three years ago".
City had registered a 3-1 win over Tottenham Hotspur at Wembley on Saturday.
City midfielder Kevin De Bruyne, a candidate for Player of the Year, said: "Unbelievable season for us".
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A week after spoiling City's title party, United duly handed the league to their local rivals.
Now the United boss has called on Pogba to produce more displays like that - and he says the hard work must start in training at Carrington.
At the age of 30, Jonny Evans already has ample experience of playing in the Premier League, unlike Aymeric Laporte.
"Not the defeat, I think it's too heavy, but not to win this match".
Inevitably, it will be the failures of this City team that will irritate Guardiola and his players, at the same time offering the critics the opportunity to find fault.
City are 16 points clear of second-placed United, who can only take a maximum of 15 points from their remaining five games.
Following the 20-time English champions shock defeat at home, the Portuguese tactician revealed he trusts in his ability to lead sides to Premier League glory but maintained it can not be achieved without consistent efforts from the team.