Here, Press Association Sport looks at five things the incoming manager might have learned from their performance.
1
Central defensive issues
Manchester City have looked vulnerable at the back for most of the season in the continued absence of captain Vincent Kompany
Nicolas Otamendi and Martin Demichelis have their shortcomings as a partnership and things have not looked much better when either have played with Eliaquim Mangala
They need Kompany back fit and Guardiola may want to look for a more reliable centre-back to partner him.
2
Yaya Toure conundrum
Toure, the driving force of Manchester City's midfield in recent seasons, still has many admirers and he is still capable of turning games, but evidence continues to build suggesting he could be on the decline
He certainly does not command games in the way he used to and was taken off as Manuel Pellegrini's side needed to chase the game
A younger replacement will be needed sooner or later.
3
A striker short
Hearts were in mouths in the first half when Sergio Aguero grimaced and limped slightly after taking a blow from a Leicester defender
Manchester City rely on their forward talisman for goals heavily and they cannot afford to lose him
With Wilfried Bony injured and facing an uncertain future, and Kelechi Iheanacho still finding his way, more back-up could be required.
4
Susceptible to counter-attacks
There were times in the game when Leicester seemed a class above Manchester City
The Foxes broke with speed and pierced the home back line on numerous occasions
After a period of consolidation from the visitors, it was then much the same early in the second half
Manchester City seemed unable to handle Leicester's speed.
5
Lacking an extra gear
The depth of Manchester City's talent is beyond doubt but they struggled to break down a team that had clearly done their homework
Leicester were stubborn in defence and stuck to their task with great dedication
It was difficult to crack them - but a side with title aspirations would expect to find a way.
Source : PA
Source: PA