• This was a personal and tactical triumph for Arteta, who left his role as Guardiola's assistant in December to take charge of an Arsenal team in crisis as successor to Unai Emery.
• Arteta's impact was obvious as every Arsenal player excavated their mental and physical resources to subdue City before striking with the deadly Pierre-Emerick Aubameyang as their spearhead,
Arsenal manager Mikel Arteta may have been the man with the inside track on Manchester City after those years of success standing behind Pep Guardiola in the technical area - but some of his former club's deficiencies are obvious to everyone.
First things first. This was a personal and tactical triumph for Arteta, who left his role as Guardiola's assistant in December to take charge of an Arsenal team in crisis as successor to Unai Emery.
Arteta's impact was obvious as every Arsenal player excavated their mental and physical resources to subdue City before striking with the deadly Pierre-Emerick Aubameyang as their spearhead, the Gabon striker scoring in each half.
As Arteta embraced his close friend Guardiola at the conclusion of this 2-0 win and looked forward to an FA Cup final against Chelsea or Manchester United, his old mentor faced some serious decisions about City's future.
Guardiola has built a superb Manchester City side, a purists' delight, as Arteta will know only too well after sharing two Premier League title triumphs, including a historic 100-point haul two years ago, and more history when they claimed a domestic treble by adding the League Cup and FA Cup last season.
And City can still make it their most glorious campaign by finally claiming the Champions League - but on the evidence of this season you would not trust them to pull it off.
In fact, you would not back them with total confidence against any team with a high-quality attack in their current defensive condition.
Indeed, if City play like this new La Liga champions, the revitalised Real Madrid, will still fancy their chances of overturning a 2-1 deficit when they meet in the second leg of their last-16 Champions League tie at Etihad Stadium on 7 August.
This had been a good week for Manchester City, with the Court of Arbitration for Sport overturning their two-year ban from European competitions after announcing the club was cleared of "disguising equity funds as sponsorship competitions".
It has also been a week that has magnified the frailties Guardiola simply must address if they are to flourish in those competitions in the future.
Arteta will have known those weakness but in reality they have been exposed all season as Manchester City lost nine Premier League games, leaving Liverpool to romp to their first title in 30 years with ease.
Here again at Wembley the truth was out there - for all Manchester City's aesthetic beauty and Guardiola's glorious principles, they have a soft centre and can be weak under pressure with a propensity to give away easy goals.
And Guardiola must take his share of the blame for failing to replace the ability and influence of former captain and iconic figure Vincent Kompany when he left last summer, leaving a rearguard that is quite frankly sub-standard for a club of their ambitions.
It is on nights like this that those chickens come home to roost.
Arsenal exposed them ruthlessly and brilliantly thanks to the expertise of Aubameyang and the sort of fierce discipline and determination that many regard as alien to them.
City's goalkeeper Ederson is truly outstanding and Aymeric Laporte is a world-class defender in the making.
And then the problems start.
Guardiola entrusted central defensive duties here to Laporte and 19-year-old rookie Eric Garcia, hardly a vote of confidence in England's John Stones, whose star is on the wane, while it has been obvious for some time Nicolas Otamendi is no longer fit for purpose.
City looked horribly vulnerable to pace, as exemplified by Aubameyang easing clear to score his second, while left-back is another position in need of attention.
Benjamin Mendy got the nod here but too often looks like an accident waiting to happen while Oleksandr Zinchenko is a deputy at best.
It will be no surprise to see Guardiola buy big in these areas, with Napoli's outstanding defender Kalidou Koulibaly looking just the sort of lynchpin they will need alongside Laporte.
This may seem a harsh verdict on a side that has given so much pleasure and has been so successful - but what he has seen will not be lost on a manager of Guardiola's class. Anything else would be delusion.
There are so many things right about his Manchester City but too much is wrong in that vital defensive area that makes them too beatable for a manager and club with such high ambitions.
As for Arsenal, what a week this has been for Arteta and his team.
Arsenal may be 10th in the Premier League but it would be quite a coup if Arteta could end his first season by adding to the club's record tally of 13 FA Cup triumphs.
The Gunners only had 35% possession after having just 31% in the midweek win against Liverpool, but so effective was their organisation, determination and sheer doggedness that City only managed one shot on target, their lowest since they had none in a Champions League game against Liverpool in April 2018.
In contrast, to show the total efficiency of their performance, all four of Arsenal's shots were on target. They had more shots on target in this match than they had in their three previous meetings with City combined, when they had just three.
Arteta will not take the great pleasure from his win over Guardiola. The pair are too close for that.
There is a wider context in that his Arsenal side, in its period of transition, have now beaten the new Premier League champions and the FA Cup holders inside four days. They are wins of great significance achieved with the sort of heart and character they have been accused of lacking in the past.
Manchester City and Guardiola, meanwhile, still harbour the dream of that first Champions League - but make no mistake about it, they will have to do an awful lot better than this if that goal is to be realised.