The Citizens are heading back to Manchester after a successful preseason tour of the United States.
City had a very youthful squad as part of their preseason, as many first team stars were not yet back for training.
Both Nico O'Reilly and James McAtee have impressed enough to come into the senior setup for this term.
"Every game was much better than the previous one," said Guardiola on the tour.
"Kalvin (Phillips) grew up, Erling (Haaland) grew up. Jack (Grealish) makes an incredible few games. Rico (Lewis) has been unbelievable with Oscar (Bobb). Today (James) McAtee makes his potential as a football player. Nico (O'Reilly) as well, played a high level.
"All the young player make some minutes. Today I make a debut for Stephen (Mfuni) at 16 years old. Everyone played. Some players will now be with the first team, some with the second, some for loan. Hopefully next season they'll come back.
"Both of them (McAtee and O'Reilly will be first team options). The other ones still they are not ready to play with us. They have to be loan or second team. We will see their development because it always depends on them."